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Water Supply,Sanitation& Fire



Chapter-1

WATER SUPPLY (ch)

Structure of this unit

Demand of water, Per capita demand

Learning Objectives1. Demand of water for domestic, commercial, industrial and public utility purposes as per

BIS standards

2. Per capita demand, leakage and wastage of water and its preventive measures

3. Storage and Distribution of Water

4.

Different methods of water distribution boosting water

5. gravity and pressure distribution by storage tanks of individual buildings

6. System of water supply

1.1 Demand of water for domestic, commercial, industrial and public utility purposes asper BIS standards (mh)

1.1.1 Residential Users (h)

Both engineering and behavioral practices are described.

1.1.1.1 Engineering Practices (sh)

Plumbing

An engineering practice for individual residential water users is the installation of indoor

plumbing fixtures that save water or the replacement of existing plumbing equipment with

equipment that uses less water. Low-flow plumbing fixtures and retrofit programs are permanent,

one-time conservation measures that can be implemented automatically with little or no

additional cost over their life times (Jensen, 1991). In some cases, they can even save the

resident money over the long term.

The City of Corpus Christi, for example, has estimated that an average three-member household

can reduce its water use by 54,000 gallons annually and can lower water bills by about $60 per

year if water-efficient plumbing fixtures are used (Jensen, 1991). Further support for this

conclusion is provided below.

Low-Flush Toilets. Residential demands account for about three-fourths of the total urban water

demand. Indoor use accounts for roughly 60 percent of all residential use, and of this, toilets (at

3.5 gallons per flush) use nearly 40 percent. Toilets, showers, and faucets combined represent



two-thirds of all indoor water use. More than 4.8 billion gallons of water is flushed down toilets

each day in the United States. The average American uses about 9,000 gallons of water to flush

230 gallons of waste down the toilet per year (Jensen, 1991). In new construction and building

rehabilitation or remodeling there is a great potential to reduce water consumption by installing

low-flush toilets.

Conventional toilets use 3.5 to 5 gallons or more of water per flush, but low-flush toilets (see

figure above) use only 1.6 gallons of water or less. Since low-flush toilets use less water, they

also reduce the volume of wastewater produced (Pearson, 1993).

Effective January 1, 1994, the Energy Policy Act of 1992 (Public Law 102-486) requires that all

new toilets produced for home use must operate on 1.6 gallons per flush or less (Shepard, 1993).

Toilets that operate on 3.5 gallons per flush will continue to be manufactured, but their use will

be allowed for only certain commercial applications through January l, 1997 (NAPHCC, 1992).

Even in existing residences, replacement of conventional toilets with low-flush toilets is a

practical and economical alternative. The effectiveness of low-flush toilets has been

demonstrated in a study in the City of San Pablo, California. In a 30-year-old apartment building,

conventional toilets that used about 4.5 gallons per flush were replaced with low-flush toilets that

use approximately 1.6 gallons per flush. The change resulted in a decrease in water consumption

from approximately 225 gallons per day per average household of 3® persons to 148 gallons per

day per household a savings of 34 percent! Although the total cost for replacement of the

conventional toilets with low-flush toilets was about $250 per unit (including installation), the

water conservation fixtures saved an average of $46 per year from each unit's water bill.

Therefore, the cost for the replacement of the conventional toilet with a low-flush toilet could berecovered in 5.4 years.

Toilet Displacement Devices. Plastic containers (such as plastic milk jugs) can be filled with

water or pebbles and placed in a toilet tank to reduce the amount of water used per flush. By

placing one to three such containers in the tank (making sure that they do not interfere with the

flushing mechanisms or the flow of water), more than l gallon of water can be saved per flush. A

toilet dam, which holds back a reservoir of water when the toilet is flushed, can also be used

instead of a plastic container to save water. Toilet dams result in a savings of 1 to 2 gallons of

water per flush (USEPA, l991b).

Low-Flow Showerheads. Showers account for about 20 percent of total indoor water use. By

replacing standard 4.5-gallon-per-minute showerheads with 2.5-gallon-per-minute heads, which

cost less than $5 each, a family of four can save approximately 20,000 gallons of water per year

(Jensen, 1991). Although individual preferences determine optimal shower flow rates, properly

designed low-flow showerheads are available to provide the quality of service found in higher-

volume models.



Whitcomb (1990) developed a model to estimate water use savings resulting from the installation

of low-flow showerheads in residential housing. Detailed data from 308 single-family residences

involved in a pilot program in Seattle, Washington, were analyzed. The estimated indoor water

use per person dropped 6.4 percent after low-flow showerheads were installed (Whitcomb,

1990).

Faucet Aerators. Faucet aerators, which break the flowing water into fine droplets and entrain

air while maintaining wetting effectiveness, are inexpensive devices that can be installed in sinks

to reduce water use. Aerators can be easily installed and can reduce the water use at a faucet by

as much as 60 percent while still maintaining a strong flow. More efficient kitchen and bathroom

faucets that use only 2 gallons of water per minute--unlike standard faucets, which use 3 to 5

gallons per minute--are also available (Jensen, 1991).

Pressure Reduction. Because flow rate is related to pressure, the maximum water flow from a

fixture operating on a fixed setting can be reduced if the water pressure is reduced. For example,

a reduction in pressure from 100 pounds per square inch to 50 psi at an outlet can result in a

water flow reduction of about one-third (Brown and Caldwell, 1984).

Homeowners can reduce the water pressure in a home by installing pressure-reducing valves.

The use of such valves might be one way to decrease water consumption in homes that are

served by municipal water systems. For homes served by wells, reducing the system pressure can

save both water and energy. Many water use fixtures in a home, however, such as washing

machines and toilets, operate on a controlled amount of water, so a reduction in water pressure

would have little effect on water use at those locations.

A reduction in water pressure can save water in other ways: it can reduce the likelihood of

leaking water pipes, leaking water heaters, and dripping faucets. It can also help reduce

dishwasher and washing machine noise and breakdowns in a plumbing system.

A study in Denver, Colorado, illustrates the effect of water pressure on water savings. Water use

in homes was compared among different water pressure zones throughout the city. Elevation of a

home with respect to the elevation of a pumping station and the proximity of the home to the

pumping station determine the pressure of water delivered to each home. Homes with high water

pressure were compared to homes with low water pressure. An annual water savings of about 6

percent was shown for homes that received water service at lower pressures when compared tohomes that received water services at higher pressures.

Gray Water Use. Domestic wastewater composed of wash water from kitchen sinks and tubs,

clothes washers, and laundry tubs is called gray water (USEPA, 1989). Gray water can be used

by homeowners for home gardening, lawn maintenance, landscaping, and other innovative uses.

The City of St. Petersburg, Florida, has implemented an urban dual distribution system for



reclaimed water for nonpotable uses. This system provides reclaimed water for more than 7,000

residential homes and businesses (USEPA, 1992).

Landscaping

Lawn and landscape maintenance often requires large amounts of water, particularly in areaswith low rainfall. Outdoor residential water use varies greatly depending on geographic location

and season. On an annual average basis, outdoor water use in the arid West and Southwest is

much greater than that in the East or Midwest. Nationally, lawn care accounts for about 32

percent of the total residential outdoor use. Other outdoor uses include washing automobiles,

maintaining swimming pools, and cleaning sidewalks and driveways.

Landscape Irrigation. One method of water conservation in landscaping uses plants that need

little water, thereby saving not only water but labor and fertilizer as well (Grisham and Fleming,

1989). A similar method is grouping plants with similar water needs. Scheduling lawn irrigation

for specific early morning or evening hours can reduce water wasted due to evaporation during

daylight hours. Another water use efficiency practice that can be applied to residential landscape

irrigation is the use of cycle irrigation methods to improve penetration and reduce runoff. Cycle

irrigation provides the right amount of water at the right time and place, for optimal growth.

Other practices include the use of low-precipitation-rate sprinklers that have better distribution

uniformity, bubbler/soaker systems, or drip irrigation systems (RMI, 1991).

Xeriscape Landscapes. Careful design of landscapes could significantly reduce water usage

nationwide. Xeriscape landscaping is an innovative, comprehensive approach to landscaping for

water conservation and pollution prevention. Traditional landscapes might incorporate one ortwo principles of water conservation, but xeriscape landscaping uses all of the following:

planning and design, soil analysis, selection of suitable plants, practical turf areas, efficient

irrigation, use of mulches, and appropriate maintenance (Welsh et al., 1993).

Benefits of xeriscape landscaping include reduced water use, decreased energy use (less

pumping and treatment required), reduced heating and cooling costs because of carefully placed

trees, decreased storm water and irrigation runoff, fewer yard wastes, increased habitat for plants

and animals, and lower labor and maintenance costs (USEPA, 1993).

More than 40 states have initiated xeriscape projects. Some communities use contests anddemonstration gardens to promote public awareness. El Paso Water Utilities and the Council of

El Paso Garden Clubs sponsor an annual "Accent Sun Country" contest. The contest spotlights

homes that have water-conserving landscapes consisting of plants and grasses that require only a

minimum of supplemental water and yet beautify the homes. The winning entries are publicized,

and cash prizes are awarded. People are invited to tour the grounds to get ideas on how they, too,

can save water, time, and money while maintaining an attractive landscape (RMI, 1991). The



offices of the Southwest Florida Water Management District in Tampa and Brooksville offer free

xeriscape tours every month. The tours begin with a slide show on the principles of xeriscape

and continue with a walking tour of water-saving landscaping (Xeriscape tours, 1993).

1.1.1.2 Behavioral Practices (sh)

Behavioral practices involve changing water use habits so that water is used more efficiently,

thus reducing the overall water consumption in a home. These practices require a change in

behavior, not modifications in the existing plumbing or fixtures in a home. Behavioral practices

for residential water users can be applied both indoors in the kitchen, bathroom, and laundry

room and outdoors.

In the kitchen, for example, 10 to 20 gallons of water a day can be saved by running the

dishwasher only when it is full. If dishes are washed by hand, water can be saved by filling the

sink or a dishpan with water rather than running the water continuously. An open conventional

faucet lets about 5 gallons of water flow every 2 minutes (Florida Commission, 1990).

Water can be saved in the bathroom by turning off the faucet while brushing teeth or shaving.

Water can be saved by taking short showers rather than long showers or baths and turning the

water off while soaping. This water savings can be increased even further by installing low-flow

showerheads, as discussed earlier. Toilets should be used only to carry away sanitary waste.

Households with lead-based solder in pipes that flush the first several gallons of water should

collect this water for alternative nonpotable uses (e.g., plant watering).

Water can be saved in the laundry room by adjusting water levels in the washing machine to

match the size of the load. If the washing machine does not have a variable load control, water

can be saved by running the machine only when it is full. If washing is done by hand, the water

should not be left running. A laundry tub should be filled with water, and the wash and rinse

water should be reused as much as possible.

Outdoor water use can be reduced by watering the lawn early in the morning or late in the

evening and on cooler days, when possible, to reduce evaporation. Allowing the grass to grow

slightly taller will reduce water loss by providing more ground shade for the roots and by

promoting water retention in the soil. Growing plants that are suited to the area ("indigenous" plants) can save more than 50 percent of the water normally used to care for outdoor plants.

As much as 150 gallons of water can be saved when washing a car by turning the hose off

between rinses. The car should be washed on the lawn if possible to reduce runoff.

Additional savings of water can result from sweeping sidewalks and driveways instead of hosing

them down. Washing a sidewalk or driveway with a hose uses about 50 gallons of water every 5



minutes (Florida Commission, 1990). If a home has an outdoor pool, water can be saved by

covering the pool when it is not in use.

1.1.2 Industrial/Commercial Users (h)

Industrial/commercial users can apply a number of conservation and water use efficiency practices. Some of these practices can also be applied by users in the other water use categories.

1.1.2.1 Engineering Practices (sh)

Water Reuse and Recycling

Water reuse [BROKEN] is the use of wastewater or reclaimed water from one application such

as municipal wastewater treatment for another application such as landscape watering. The

reused water must be used for a beneficial purpose and in accordance with applicable rules (such

as local ordinances governing water reuse). Some potential applications for the reuse ofwastewater or reclaimed water include other industrial uses, landscape irrigation, agricultural

irrigation, aesthetic uses such as fountains, and fire protection (USEPA, 1992). Factors that

should be considered in an industrial water reuse program include (Brown and Caldwell, 1990):

• Identification of water reuse opportunities

• Determination of the minimum water quality needed for the given use

• Identification of wastewater sources that satisfy the water quality requirements

• Determination of how the water can be transported to the new use

The reuse of wastewater or reclaimed water is beneficial because it reduces the demands on

available surface and ground waters (Strauss, 1991). Perhaps the greatest benefit of establishing

water reuse programs is their contribution in delaying or eliminating the need to expand potable

water supply and treatment facilities (USEPA, 1992). Water recycling [BROKEN] is the reuse of

water for the same application for which it was originally used. Recycled water might require

treatment before it can be used again. Factors that should be considered in a water recycling

program include (Brown and Caldwell, 1990):

• Identification of water reuse opportunities

• Evaluation of the minimum water quality needed for a particular use

• Evaluation of water quality degradation resulting from the use

• Determination of the treatment steps, if any, that might be required to prepare the water

for recycling

Cooling Water Recirculation



The use of water for cooling in industrial applications represents one of the largest water uses in

the United States. Water is typically used to cool heat-generating equipment or to condense gases

in a thermodynamic cycle. The most water-intensive cooling method used in industrial

applications is once-through cooling, in which water contacts and lowers the temperature of a

heat source and then is discharged.

Recycling water with a recirculating cooling system can greatly reduce water use by using the

same water to perform several cooling operations. The water savings [BROKEN]are sufficiently

substantial to result in overall cost savings to the industry (see box). Three cooling water

conservation approaches that can be used to reduce water use are evaporative cooling, ozonation,

and air heat exchange (Brown and Caldwell, 1990).

In industrial/commerical evaporative cooling systems, water loses heat when a portion of it is

evaporated. Water is lost from evaporative cooling towers as the result of evaporation, drift, and

blowdown. (Blowdown is a process in which some of the poor-quality recirculating water is

discharged from the tower in order to reduce the total dissolved solids.) Water savings associated

with the use of evaporative cooling towers can be increased by reducing blowdown or water

discharges from cooling towers.

The use of ozone to treat cooling water (ozonation) can result in a five-fold reduction in

blowdown when compared to traditional chemical treatments and should be considered as an

option for increasing water savings in a cooling tower (Brown and Caldwell, 1990).

Air heat exchange works on the same principle as a car's radiator. In an air heat exchanger, a fan

blows air past finned tubes carrying the recirculating cooling water. Air heat exchangers involveno water loss, but they can be relatively expensive when compared with cooling towers (Brown

and Caldwell, 1990).

The Pacific Power and Light Company's Wyodak Generating Station in Wyoming decided to use

dry cooling to eliminate water losses from cooling-water blowdown, evaporation, and drift. The

station was equipped with the first air-cooled condenser in the western hemisphere. Steam from

the turbine is distributed through overhead pipes to finned carbon steel tubes. These are grouped

in rectangular bundles and installed in A-frame modules above 69 circulating fans. The fans

force some 45 million cubic feet per minute (ft3/min) of air through 8 million square feet of

finned-tube surface, condensing the steam (Strauss, 1991).

The payback comes from the water savings. Compared to about 4,000 gallons per minute

(gal/min) of makeup (replacement water) for equivalent evaporative cooling, the technique

reduces the station's water requirement to about 300 gal/min (Strauss, 1991).

Rinsing



Another common use of water by industry is the application of deionized water for removing

contaminants from products and equipment. Deionized water contains no ions (such as salts),

which tend to corrode or deposit onto metals. Historically, industries have used deionized water

excessively to provide maximum assurance against contaminated products. The use of deionized

water can be reduced without affecting production quality by eliminating some plenum flushes (a

rinsing procedure that discharges deionized water from the rim of a flowing bath to remove

contaminants from the sides and bottom of the bath), converting from a continuous-flow to an

intermittent-flow system, and improving control of the use of deionized water (Brown and

Caldwell, 1990).

Deionized water can be recycled after its first use, but the treatment for recycling can include

many of the processes required to produce deionized water from municipal water. The reuse of

once-used deionized water for a different application should also be considered by industry,

where applicable, because deionized water is often more pure after its initial use than municipal

water (Brown and Caldwell, 1990).

Landscape Irrigation

Another way that industrial/commercial facilities can reduce water use is through the

implementation of efficient landscape irrigation practices. There are several general ways that

water can be more efficiently used for landscape irrigation, including the design of landscapes

for low maintenance and low water requirements (refer to the previous section on xeriscape

landscaping), the use of water-efficient irrigation equipment such as drip systems or deep root

systems, the proper maintenance of irrigation equipment to ensure that it is working properly, the

distribution of irrigation equipment to make sure that water is dispensed evenly over areas whereit is needed, and the scheduling of irrigation to ensure maximum water use (Brown and Caldwell,

1990). For additional information on efficient water use for irrigation, refer to the practices for

residential users and agricultural users in this chapter.

1.1.2.2 Behavioral Practices (sh)

Behavioral practices involve modifying water use habits to achieve more efficient use of water,

thus reducing overall water consumption by an industrial/commercial facility. Changes in

behavior [BROKEN] can save water without modifying the existing equipment at a facility.

Monitoring the amount of water used by an industrial/commercial facility can provide baseline

information on quantities of overall company water use, the seasonal and hourly patterns of

water use, and the quantities and quality of water use in individual processes. Baseline

information on water use can be used to set company goals and to develop specific water use

efficiency measures. Monitoring can make employees more aware of water use rates and makes

it easier to measure the results of conservation efforts. The use of meters on individual pieces of



water-using equipment can provide direct information on the efficiency of water use. Records of

meter readings can be used to identify changes in water use rates and possible problems in a

system (Brown and Caldwell, 1990).

Many of the practices described in the section for residential users can also be applied by

commercial users. These include low-flow fixtures, water-efficient landscaping, and water reuse

and recycling (e.g., using recycled wash water for pre-rinse).

1.1.3 Planning and Management Practices (h)

In addition to engineering practices, system operators can use several other practices to conserve

water or improve water use efficiency.

Pricing

Information and education promoting conservation do not appear to be effective by themselvesin achieving a conservation goal without at the same time imposing significant price increases to

provide a financial incentive to conserve water (Martin and Kulakowski, 1991). Customers use

less water when they have to pay more for it and use more when they know they can afford it.

However, most people consider water to be a "free good" and are not willing to pay higher prices

that reflect the true costs associated with the water delivered to their homes. Rate structures have

the advantage of avoiding the costs of overt regulation, restrictions, and policing while retaining

a greater degree of individual freedom of choice for water customers.

Overall charges for water service increased at an average compound rate of 7 percent per year

during the 1980s nearly double the rate of inflation (Russet and Woodcock, 1992). There is

concern over "price gouging" due to increased water rates (Collinge, 1992). Some pricing has

been objected to on the grounds that it can lead to a substantial excess of revenues over costs an

excess that might be inequitable and, in some states, unconstitutional (Collinge, 1992).

Water utility managers must establish and design water rates that meet revenue requirements and

are fair and equitable to all customer classes in the water system. This task involves the

following procedures:

• Determination of the water utility's total annual revenue requirements for the period for

which the rates are to be in effect

• Determination of service costs by allocation of the total annual revenue requirements to

the basic water system cost components and distribution of these costs to the various

customer classes in accordance with their service requirements

• Design of water rates to recover the cost of service from each class of customer (Mui et

al., 1991)



Several price rate structuring alternatives are available for water system operators.

Increasing Block Rate, or Tiered, Pricing. Increasing block rate, or tiered, pricing reduces

water use by increasing per-unit charges for water as the amount used increases. For example,

the first volume of water (block) used is charged a base rate, the second block is charged the base

rate plus a surcharge, and the third block is charged the base rate plus a higher surcharge. It is

necessary to increase real prices significantly to overcome the effects of conservation (Martin

and Kulakowski, l991).

For example, as the cost of water increased in Tucson, Arizona, residents used 33 percent less

water between 1974 and 1980. A 10 percent increase in water rates provided about 3 percent

more revenue while triggering a 7 percent reduction in use (Billings and Day, 1989). Using

seasonal increasing block rate pricing during summer and winter months, to encourage year-

round conservation, resulted in estimated water savings for the single-family residential class in

Tucson of an average 2.23 Mgal/d during 1983-1986 (Cuthbert, 1989).

Decreasing Block Rate Pricing. Decreasing block rate prices reflect per-unit costs of

production and delivery that go down as customers consume more water.

The monthly water use records of 101 customers were measured in a study of municipal water

use in the city of Denton, Texas. Summer water use records from 1976 to 1980 during a

decreasing block rate period were compared to summer use records from 1981 to 1985 during an

increasing block rate period. It was found that the decreasing block rate scenario encouraged

greater water use, whereas the increasing block rate scenario resulted in a reaction to the price

increase and a corresponding decrease in water use (Nieswiadomy and Molina, 1989).

Time-of-Day Pricing. Time-of-day pricing charges users relatively higher prices during a

utility's peak use periods. Because customers are sensitive to price increases, these charges

curtail demand. Time-of-day pricing can cut generating capacity and reduce reliance on

expensive secondary fuel sources (Sexton et al., 1989).

Water Surcharges. A water surcharge imposes a higher rate on excessive water use. The

customer pays more money per gallon for water use that is considered higher-than-average.

Surcharges include unit surcharges, winter/ summer ratios, and alternative seasonal rates. Theunit surcharge method establishes a threshold level for excess consumption based on average

daily per capita or per-household consumption. A surcharge is imposed for all water use above

that threshold level. For the winter/summer ratio, metered water use during the winter period is

compared to consumption during the corresponding summer period, and a higher rate or

surcharge is imposed for water consumption above the average winter use. Typically, an increase

in usage of 14-20 percent occurs during the summer. Under an alternative seasonal rate structure,



all water used during the summer or peak season is billed at a higher rate than that used during

the other seasons. The increased rate is applied to all customers at all water-use levels (Schlette

and Kemp, 1991).

Retrofit Programs

Retrofit programs are another tool system operators can use to promote water use efficiency

practices. Retrofitting involves the replacement of existing plumbing equipment with equipment

that uses less water. The most successful water-saving fixtures are those which operate in the

same manner as the fixtures they are replacing--for example, toilet tank inserts, shower flow

restrictors, and low-flow showerheads. (For more information, refer to the practices for

residential users.) As discussed previously, retrofit programs are permanent, one-time

conservation measures that can be implemented with little or no additional cost over their

lifetimes (Jensen, 1991).

A retrofit program can involve the use of education programs to let users know which fixtures

are best, where to get them, and how to install them. System operators can also purchase water-

efficient fixtures and resell them at cost to the users, but the most successful retrofit programs

have been those in which the system operator purchases, distributes, and installs the fixtures.

Retrofit programs have been shown to be cost-effective and useful in conserving water in many

cases. An apartment building in New England with 151 units was retrofitted with low-flow

showerheads and faucet aerators at a cost of $1,074. As a result of the retrofit 1,725,000 gallons

of water, $8,590 for energy, and $980 for water were saved in 1 year. In another retrofit program,

the Lower Colorado River Authority installed low-flow showerheads and toilet dams in anapartment complex and public housing program in Marble Falls, Texas. Indoor per capita water

use was reduced by 21 percent (from 81 to 64 gal/cap/day) in the apartment complex and was

reduced 11 percent (from 102 to 91 gal/cap/day) in the public housing program (Jensen, 1991).

Current use of low-flow toilets throughout Texas could reduce the need to build new water and

wastewater treatment plants by 15 percent, resulting in a savings of as much as $3.4 billion

during the next 50 years. Residential water and sewer bills could also be reduced by as much as

$200 million over the long term. The Texas Water Development Board estimates that the use of

water-efficient plumbing fixtures should save a typical four-member household 55,800 gallons of

water and $627 in reduced water and energy costs per year. The Board estimates that the use oflow-flow fixtures might reduce water use statewide by 805 Mgal/d by the year 2040 (Jensen,

1991).

Retrofit programs can be combined with water audit programs (discussed below) to further

improve potential water savings.



Residential Water Audit Programs

Residential water audit programs involve sending trained water auditors to participating family

homes, free of charge, to encourage water conservation efforts. Auditors visit participating

homes to identify water conservation opportunities, such as repairing leaks and low-flow

plumbing, and to recommend changes in water use practices to reduce home water use. The audit

programs try to stretch existing water supplies by getting water users to use water more

efficiently (Whitcomb, 1990). The largest percentage of indoor use comes from bathing and

toilet flushing. Therefore, the bathroom is an ideal place for water system operators to focus

water conservation efforts (Grisham and Fleming, 1989).

Public Education

Public education programs can be used to inform the public about the basics of water use

efficiency:

• How water is delivered to them

• The costs of water service

• Why water conservation is important

• How they can participate in conservation efforts

Public education is an essential component of a successful water conservation program. A

number of tools can be used to educate the public [BROKEN]: bill inserts, feature articles and

announcements in the news media, workshops, booklets, posters and bumper stickers, and the

distribution of water-saving devices. Public school education is also an important means for

instilling water conservation awareness (Grisham and Fleming, 1989).

Another way to provide public information and education, as well as to collect real-world data on

water conservation and use efficiency, is through the use of demonstration projects. In Tucson,

Arizona, the Casa del Agua, a single-family home, has been used to demonstrate and study water

conservation and reuse techniques and technologies. In 1985, the University of Arizona designed

and retrofitted the Casa del Agua with water-conserving fixtures, a rainwater harvesting system,

gray water reuse and storage systems, and drought-tolerant plants. Measurements of water use

and water quality at the Casa del Agua have provided a useful collection of data for evaluating

the possible benefits of conservation techniques and technologies in a residential home.

A study of water demand in the United States using American Water Works Association

(AWWA) data indicated that water users are more sensitive to a change in price in the South and

the West than in the other regions of the country. Public education appears to have reduced water

usage in the West.



A heightened awareness of water's scarcity might make educational programs more effective in

the West than in the rest of the country (Nieswiadomy, 1992).

Index of Water Efficiency

An index of water efficiency, or "W-Index," can be used as a device to evaluate residential watersavings and as a way to motivate water users to adopt water-saving practices. A W-Index can

serve as a measure of the effectiveness of water efficiency features in a home. The index

provides a calculated numerical value for each dwelling unit, which is derived from the number

and kind of water-saving features present, including indoor and outdoor water savers and water

harvesting or recycling systems. Architects, builders, appraisers, homeowners, water suppliers,

or water management agencies can use the W-Index as a basis for evaluating the water-saving

capability of any particular single- or multi-family dwelling unit (DeCook et al., 1988).

Typically, an overall W-Index rating of W-50 would be considered fair, W-80 good, and W-110

excellent, based on a specific set of community water conservation goals (DeCook et al., 1988).

The W-Index has been applied to the Casa del Agua, the Tucson, Arizona, water conservation

demonstration home discussed in the preceding section. The Casa del Agua received a value of

W-139. The index was applied to about 30 other homes in the Tucson area, with resulting values

ranging from W-75 to W-100.

Planning for Resource Protection

Monitoring and managing land use and waste disposal practices around water supply sources can

potentially reduce the need for new water supply development and keep water treatment costs to

a minimum (Gollnitz, 1988). Adverse effects on a water supply source can be lessened through

land use controls such as land preservation, nonregulatory and regulatory watershed programs,

environmental assessment requirements, and zoning (Gollnitz, 1988). The protection of a water

source by a utility can range from simple sanitary surveys of a watershed to the development and

implementation of complex land use controls.

Water supply source protection should play an important role in the overall management of a

municipal water utility. Contamination of a water source can result from point and nonpoint

sources of pollution such as chemical spills, waste discharges, or the improper use and runoff of

insecticides and herbicides. The contamination of a water supply source can result in the need todevelop expensive treatment systems or to find new sources for water supply.

Drought Management Planning

When less rain falls than usual, there is less water to maintain normal soil moisture, stream

flows, and reservoir levels and to recharge ground water. Falling levels of surface waters create



unattractive areas of exposed shoreline and reduce the capacity of surface waters to dilute and

carry municipal and industrial wastewater. Water quality often decreases as water quantity

decreases, adversely affecting fish and wildlife habitats. In addition, dry conditions make trees

more prone to insect damage and disease and increase the potential for grass and forest fires

(TVA, n.d.).

A drought management plan should address a range of issues, from political and technical

matters to public involvement. Managing a resource essential to people's welfare during disaster

and dealing with the associated emotional, economic, and physical consequences makes drought

management a very challenging task.

1.2 Per capita demand, leakage and wastage of water and its preventive measures (mh)

Per Capita Water Supply per day is arrived normally including the following components:

a. Domestic needs such as drinking, cooking, bathing, washing, flushing of toilets,

gardening and individual air cooling.

b. Institutional needs

c. Public purposes such as street washing or street watering, flushing of sewers, watering of

public parks.

d. Minor industrial and commercial uses

e.

Fire fighting

f. Requirements of live stock and

g.

Minimum permissible Unaccounted for Water (UFW)

Water supply levels in liters per capita per day (lpcd) for domestic & non domestic purpose and

Institutional needs, as recommended by CPHEEO for designing water treatment schemes are

given at Table. The water requirements for institutions should be provided in addition to the

provisions indicated for domestic and non-domestic, where required, if they are of considerable

magnitude and not covered in the provisions already made.

Table: Per Capita Water Supply Levels for Design of Scheme

S.No. Classification of Towns / Cities LPCD

A. Domestic & Non- Domestic Needs

1. Towns provided with piped water supply but without sewerage

system

70

2. Cities provided with piped water supply sewerage system is 135



sustainability. Since fresh water resources are very unevenly distributed around the world, it is

not surprising that the per capita water supply also varies widely ranging from 50 lpcd to 800

lpcd. Keeping in view the above factors, the Working Group of the National Commission for

integrated Water Resources Development Plan, as a final goal, has suggested the norms for water

supply as 220 lpcd for urban areas and 150 lpcd for rural areas.

Central Pollution Control Board reviewed, as per the water supply status of year 1995, the total

water supply in Class I cities was 20545 mld and per capita water supply was 182 litres. In case

of Class II cities, the total water supply was 1936 mld and per capita water supply was 103 liters.

Per capita water supply for metropolitan cities estimated based on the information obtained are

given at Table. Also per capita water supply variations in different states are summarized at

Table. It is observed that a minimum and maximum per capita water supply figure is reported

for Kerala state as 12 lpcd and 372 lpcd.

Table: Per Capita Water Supply for Metropolitan Cities

S.No. Name ofcity

Population*

WTP Installed capacity(MLD)

LPCD

1. Bangalore 6523110 900 138

2. Chennai 4216268 573.8 136

3. Delhi 13782976 2118 154

4. Hyderabad 3686460 668 181

5. Kolkata 11021918 909 83

6. Mumbai 11914398 3128 263

1.2.1

Leakage and wastage in the public drinking-water supply system (h)

No public supply is completely leak proof; not even the best-designed and carefully constructed

system can remain absolutely watertight throughout its life. An efficient public drinking-water

supply authority will therefore maintain a continuous program of inspection and preventive

maintenance to discover and stop leakage for both financial and health reasons. Unaccounted-for

water represents a lost opportunity for the authority to earn income from the supply of water.

Leaks that allow water to flow out of the system can also provide the means of entry for

contaminants, which may in turn cause illness. A further reason to maintain a continuous program of inspection and timely implementation of repairs to the public drinking-water supply

mains is that it sets an example for the owners of private properties to maintain their own

drinking-water supply systems so as to minimize waste.

Wastage below ground is difficult to detect and isolate and often expensive to remedy. The

best strategy is therefore to ensure that the drinking-water supply systems are built to the highest

possible standards. The selection of materials, installation practices and workmanship in both



public and private drinking-water supply systems should all contribute to reducing the incidence

of unseen wastage. The usual procedure for tracing these leaks in the mains system is a

combination of district metering and inspection of the mains and services with a leak detection

system such as a listening device between midnight and dawn when supply demands are low.

This can be followed by the investigation of suspect properties.

1.2.2

Leakage and wastage from private drinking-water supply systems (h)

Leakage from piping systems within a building is usually self-evident because it threatens to

damage the building structure and internal walls and fittings. It is in the interest of the owner of

the property to have this remedied promptly, especially since a leak can become progressively

worse as the escaping water increases the size of the orifice through which it emerges. In certain

situations, especially where water charges are not based on metered volumes of water used,

powers of enforcement may have to be used to compel those responsible to undertake repairs.

Another type of wastage is very difficult to control without the cooperation of the building’s

occupants, namely that due to leaking taps, valves or incorrectly adjusted fittings in fixtures suchas washbasins or toilet cisterns. Because the wastewater is conveyed through the fixture to the

drainage system or is discharged through an overflow, it may cause no obvious nuisance within

the building, and therefore there is less incentive for the property owner to take action to fix the

leak. In large buildings, factories or high-density housing estates, the total wastage due to this

cause may be very considerable. The actual cost of replacing worn washers and adjusting leaking

fittings is minor once the leaks have been identified. Because of this, some drinking-water supply

authorities offer to carry out simple remedial works or repairs free of charge to consumers, thus

encouraging them to report such faults at an early stage.

1.3 Storage and Distribution of Water (mh)

The following storage and distribution systems are described in the Fact Sheets:

Storage — concrete-lined earthen reservoir;

— reinforced concrete reservoir;

— elevated steel reservoir;

— ferrocement tank.

Distribution — Public stand post;

— Domestic connection;

— Small flow meter.



These lists are not exhaustive, but have been selected as being most relevant to small,

community water-supply systems. Of the storage options reviewed, the concrete-lined earthen

reservoir is the only system that is suitable for storing raw water, and the O&M of such a system

should consider the possibility that a raw water source will be used. A water lifting method to get

the raw water to the storage reservoir may be necessary and this should also be considered in the

O&M implications. In many cases, a concrete-lined earthen reservoir can be used instead of open

concrete reservoirs. Flow meters are only discussed in general, and no comparison is made

between types and brands, because this is outside the scope of this manual. However, the

decision to install flow meters has important operational and organizational implications.

Material selection The type of material chosen for the pipes and accessories will determine the

maintenance activities that will be needed. Both polyvinyl chloride (PVCu) and polyethylene

(PE) are used in drinking-water networks, but PE is more commonly used for smaller diameter

pipes and with lower water pressures. It comes in rolls that are 50 m or 100 m long and is more

flexible than PVCu. PVCu comes as pipes 6 m in length and up to 300 mm in diameter(sometimes more). Commonly, more accessories are available for PVCu than for PE, but PVCu

is more easily fractured by poor handling and laying techniques. However, when properly

installed, PVCu pipes need hardly any maintenance, except for controlling leaks.

Asbestos cement pipes are made with external diameters from 100 mm to over 1000 mm. They

are not suitable for use with high water pressures, but they are relatively cheap. Asbestos cement

pipes cannot be installed in aggressive soils, since they are susceptible to corrosion. Because of

their rigidity, asbestos cement pipes require careful handling when they are installed, to avoid

damaging them. In areas with high water pressure (above the local standard pressure), pressure-

reducing valves should be considered to reduce the amount of water lost to leakage. For water pressures greater than 1.25 Mpa (about 127-m head of water) metal pipes should be used. Metal

pipes should also be used if they are to be laid on the surface and exposed to sunlight. The

following are some features of metal piping and accessories:

— metal pipelines are generally sensitive to corrosion;

— galvanized-iron pipes are supplied in diameters of up to 4 inches (100 mm nominal bore), and

steel pipes are supplied in larger diameters;

— ductile iron pipes are similar to steel pipes, but they are more resistant to corrosion;

— cast iron has good resistance to corrosion and is used for accessories, such as connectors and

valves, but it is hard and breaks more easily than ductile iron.

Galvanization gives some protection against corrosion, but most metal pipes need to have

internal and external protection. Examples of internal protective linings are epoxy resin and

cement mortar. Bituminous lining should be avoided because of possible health risks. All

internal coatings must be carried out during the manufacturing process, but relinining or



replacing the piping should be part of O&M activities. External protective coating is beneficial

when pipes are laid in corrosive soil conditions. Examples of materials used in external coating

include zinc oxide, bitumen paint and polythene sleeving. External coating is usually applied

during manufacture, but polythene sleeving can be applied when laying the pipe.

1.3.1

Concrete-lined earthen reservoir1 (h)

1.3.1.1

The technology (sh)

Lined earthen reservoirs can be built in natural depressions, or constructed by excavating and

building a dam around the reservoir. If possible, the quantities of excavation and refill are kept

nearly identical, to minimize the amount of work. The inner and outer walls of such a reservoir

are always sloped, and inlets and outlets are installed during the earthwork. The walls and

bottom of the reservoir must be compacted, especially the parts made by refilling. The inside of

the reservoir is waterproofed by a lining of concrete, which is usually poured on-site in largeslabs. The slab size is limited by the ability of the concrete slab to support its own weight when it

is moved into place during construction of the reservoir. Once in place, the slabs are connected

by a sealing of waterproof material. More recently, reservoirs have been constructed using a

single slab of concrete, using ferrocement technology. Linings can also be made of clay, loam or

plastic.

1.3.1.2 Volume of reservoir (sh)

From a few cubic metres to many thousands.

1.3.1.3 Uses (sh)

De-silting and storing raw water.



1.3.1.4

Main O&M activities (sh)

Operation of a reservoir consists of opening and closing the inlet and outlet valves and sluices,

according to water need in the system and water quality at the inlet. The valves and sluices

should be opened and closed at least every two months to prevent them sticking. At least once a

year, the reservoir should be emptied of sediment and cleaned, and the lining inspected and

disinfected with chlorine. Cracks or other damage to the lining should be repaired. Usually, the

cleaning of a reservoir is a communal activity, which can be organized by a water committee that

coordinates all the activities related to the system. An individual living near the reservoir can be

assigned the job of caretaker.

1.3.2 Reinforced concrete reservoir1 (h)

1.3.2.1 The technology (sh)

Reinforced concrete reservoirs are used to store clean water for release on demand. They areusually made of concrete reinforced with steel bars or steel mesh, although some low-cost

construction techniques use bamboo or other materials to reinforce the concrete. Reservoirs may

also be made of masonry, or ferrocement. Chemical additives are often mixed with the concrete

to make it more impermeable to water. Reinforced concrete reservoirs are built at the site on a

solid foundation. If the base is not solid enough, another site should be chosen, or arrangements

made to stabilize the construction.



To protect the water from contamination, the reservoir is covered with a roof, usually made of

reinforced concrete, but other materials can be used. In the top of the tank an aeration pipe with a

screen allows fresh air to circulate in the tank, but keeps rodents and insects out. A manhole in

the roof allows access to the tank for cleaning and repairs. Water flows into the reservoir through

an inlet pipe above the water level in the reservoir. This prevents back-flow and allows the water

to be heard entering the tank. At this point, a chlorine solution is often added for disinfection.

Outlets are built a little above the floor of the reservoir, which has a slope pitched down towards

one point with a washout pipe for flushing.

Range of depth: Usually between 1.5–3.0 m.

Expected useful lifetime: 30 years.

Use: For reservoirs larger than about 3 m3 where sand, cement, gravel and reinforcing

materials are available.

1.3.2.2


Operation consists of opening and closing the valves, and managing a chlorinator, if provided. If

the reservoir does not deliver directly to a tap, water distribution is usually carried out by a

caretaker. A well-designed and well-built reservoir needs very little maintenance. The

surroundings must be kept clean on a regular basis; every two months the valves must be closed

and opened to prevent them from sticking, and the screens must be checked. Occasionally, a



screen or tap may need to be repaired. Once a year, or sooner if contamination is suspected, the

reservoir must be drained, de-silted, cleaned with a brush and disinfected with chlorine. Any

leaks or cracks in the concrete have to be repaired as soon as possible. If needed, a caretaker can

be appointed to regulate the inflow and outflow. A concrete reservoir has few other

organizational requirements.

1.3.3 Elevated steel reservoir (h)


An elevated steel reservoir stores clean water in a steel tank on a raised stand or tower. The

elevation of the tank provides the water pressure to all points in the pressure zone of the

distribution system. Tanks may be cylindrical, rectangular or any other convenient shape. For

family use, the tank can be made of an old oil drum (duly coated), and the tower of bamboo. For

communal needs, elevated steel tanks are often constructed from factory-made galvanized steelelements bolted or welded together. However, even with galvanization, steel tanks are generally

more sensitive to corrosion than concrete reservoirs. On the other hand, steel tanks can be built

faster and the cost of transporting the material is generally lower, especially when concrete

aggregates are not locally produced. Several pipes are connected to the tank, including ones for

inlet, outlet, overflow and washout, and a screened vent hole or pipe maintains atmospheric

pressure in the tank. There is also an entryway in the cover of the reservoir to allow the reservoir

to be inspected. The entryway is normally kept closed with a lid. If an electric pump is used to

pump water into the reservoir, the water level in the reservoir can be regulated by sensor

electrodes in the tank. Alternatively, a float valve may be used to cut off the inflow when the

maximum level has been reached. The tanks may be placed on steel, wooden or reinforced-concrete towers, and special attention must be given to the foundation structure. Big elevated

steel tanks are typically used by major water users, such as agricultural enterprises and

communities.

Initial cost: Prices vary considerably between countries and tank quality. In 1991, in Tanzania, a

circular above-ground tank made of galvanized iron cost US$ 125 for a 1 m3 tank (US$ 125 per

m3) and US$ 550 for a 10 m3 tank (US$ 55 per m3) (Mayo, 1991).



1.3.3.2 Main O&M activities (sh)

Operation consists of opening and closing the valves, and managing a chlorinator if one is used.This is usually done by a caretaker who lives nearby. For maintenance, the valves must be

opened and closed every two months to prevent them from sticking. Some valves need

lubricating. The screens must also be checked, and occasionally a screen or valve may need to be

repaired. The inside of the reservoir should be cleaned at least every six months and disinfected

using a chlorine solution. The tank and the stand should be painted once a year – epoxy-paint

coatings should need little maintenance. Any leaks should be repaired immediately.

1.3.4

Ferrocement tank 1 (h)

1.3.4.1

The technology (sh)

Ferrocement water tanks are made of steel mesh and wire, covered on the inside and outside with

a thin layer of cement-and-sand mortar. The walls may be as thin as 2.5 cm. The tanks can be

used for individual households or for whole communities, and they provide a relatively

inexpensive and easy-to-maintain storage method. To avoid bending forces in the material, most



ferrocement tanks have curved walls, in the form of a cylinder, a globe or an egg. Compared to

concrete reservoirs, ferrocement tanks are relatively light and flexible. To protect the water from

contamination, the tank is covered with a lid or a roof that can be made of various materials, but

is usually ferrocement. In this case, an aeration pipe with a screen is needed to allow fresh air to

circulate in the tank, while keeping out rodents and insects. A manhole in the roof gives access to

the tank for cleaning and repairs. Water flows into the reservoir through an inlet pipe, which is

normally above the water level. Often, a chlorine solution is added to the stored water for

disinfection. Outlets are built a little above the floor of the reservoir, which slopes down towards

a washout pipe for flushing into a drain. The site is fenced, to keep out cattle that can damage the

thin walls of the reservoir.

Initial cost: In Kenya in 1993, a 20 m3 tank with a roof cost US$ 420 (US$ 21 per m3;

Cumberlege & Kiongo, 1994). In the South Pacific Islands in 1994, 5.5–12 m3 tanks cost an

average of US$ 50 per m3 (Skoda & Reynolds, 1994).

Range of volume: From 1 m3 to over 80 m3.Range of depth: Usually, between 1.5–3.0 m.

Area of use: Anywhere that inexpensive storage is needed.

Manufacturers: Ferrocement tanks are built on-site by many organizations, craftsmen and

building contractors, and can even be factory made.




Operation consists of opening and closing the valves, and managing a chlorinator, if provided. A

ferrocement tank that is well-designed and well-built needs very little maintenance. The

surroundings, including the drain, must be kept clean on a regular basis; every two months, the

valves must be opened and closed to prevent them sticking, and the screens must be checked.

Occasionally the fence, a screen or tap may need repair. Every six months, or when

contamination is suspected, the reservoir must be drained, de-silted, cleaned with a brush, and

disinfected with chlorine. Any leaks have to be repaired immediately. Repair involves some

special techniques using wire and mesh, cement, sand and water, but they are easy to learn.

Ferrocement tanks can be used at the family or communal level. If used by communities, a

caretaker can be appointed, preferably someone who lives close to the reservoir.

1.3.5 Public standpost1 (h)


A public standpost or tapstand distributes water from one or more taps to many users. Because it

is used by many people it is often not looked after, and the design and construction must be

sturdier than used in similar domestic connections. A standpost includes a service connection to

the supplying water pipeline, a supporting column or wall made of wood, brick, dry stone

masonry, concrete, etc, and one or more 0.5 inch (1.25 cm) taps that protrude far enough from

the column or wall to make it easy to fill the water containers. The taps can be a globe or a self-closing type. The residual pressure head of the water at the standpost should be 10–30 m, and

some standposts have a regulating valve in the connection to the mains that can be set and locked

to limit the maximum flow. A water meter may also be included (see Fact Sheet 7.8 Domestic

water meters). A solid stone or concrete apron under the taps, and a drainage system, lead spilled

water away and prevent muddy pools from forming. A fence may be needed to keep cattle away.

The location and design of a public standpost should be determined in close cooperation with

future users.



1.3.5.2


Water users clean and fill their containers at the tap (bathing and washing clothes are not usually

permitted at the standpost itself). At all times, pools of water must be prevented. The tap site

should be cleaned daily and the drain inspected. The drain must be cleaned at least once a month.

Occasionally, a rubber washer or other tap part may have to be replaced, and the fence may need

to be repaired. If the standpost structure becomes cracked, it must be repaired, and when wood

rots it must be treated or replaced. Occasionally, the piping may leak and need to be replaced. A

caretaker or tap committee may be appointed to keep the tap functioning and the surroundings

clean, and to regulate the amount of water used. Committee members may Public standpost also

collect the fees for water use. Sometimes, water vendors are allowed to fill their tanks at public

standposts at special rates, for resale to people living farther away.

1.3.6 Domestic connection1 (h)

1.3.6.1

The technology (sh)



When enough water and funds are available, the best option is to connect every house or yard to

a piped water system. This is more convenient for water users, generally increases water use, and

improves hygiene. A service pipe, usually made of PE or PVCu, leads from the distribution

network to the house or yard. The domestic connection can consist of a single tap on a post, or a

system of pipes and taps in a house. A gate valve and a water meter are normally installed at the

entry to the premises. Drainage must also be provided. The residual head of water (pressure) at

household connections should be 10–30 m.

Initial cost: Depends on factors, such as whether the domestic connection extends into a house,

the type of piping material used, whether PE or PVCu pipes are available locally, etc.

Users per connection: Usually, one family.

Yield: Depends on the pressure of the public main, diameter of the household connection, and

demand.

1.3.6.2


Taps are used throughout the day. They should not be left open or leak, otherwise mud and pools

will form, which must be avoided. The tap and site must be cleaned regularly and the drain

inspected. In case of leakage, a rubber washer or other part of the tap may need to be replaced.

Any structure on the tap site and drainage system may need to be repaired. Occasionally, the

service pipe, fittings and accessories may leak and need to be repaired or replaced. O&M of the

domestic connection are carried out by the household itself, or by a community water committee.

When water is scarce, or if the pressure is too low in part of the network, the water committee

has to motivate users to limit their water use, or create conditions that will induce users to reduce

water consumption (e.g. a tariff structure that discourages excessive water use).



1.3.7 Domestic water meter1 (h)


Water meters, in combination with public standposts or domestic connections, provide the means

to charge fees according to the volume of water delivered, and to regulate water use via tariffs.

Water meters consist of a device to measure flow, and a protective housing with an inlet and an

outlet. A strainer over the inlet keeps larger particles out of the system. There are many types of

water meter, but for ordinary domestic or public standpipe use, turbine meters are most common.

The vane wheel and the counting device of a water meter can be coupled magnetically or

directly. Magnetic coupling has the advantage that the counting device can be completely sealed

and no water, silt or algae will get in. A shut-off valve is normally installed on both sides of themeter to allow for servicing.

Initial cost: From US$ 10–25 or more, not including installation costs.

Flow range: 0.005–1.5 litres/s for domestic use.

Area of use: Piped public water distribution systems.

Manufacturers: Biesinger; Bosco; Kent; Schlumberger; Spanner Pollux; Valmet, etc.




On a regular basis (e.g. every month), the water meter should be read by an appointed person

who writes down the new meter count in a book. The difference between two readings of the

same meter is the amount of water used, and consumers will be billed accordingly. The reader

must check that the meter is in good condition and has not been tampered with. Meter counts can

also serve to regulate consumption, by raising tariffs as more water is used. The fee for a meter

reader increases the operational costs of the system, but the costs may be partly offset because

the domestic water meters (and distribution network water meters) help to control leaks and the

wasting of water. When the water is free of silt, a good-quality water meter needs very little

maintenance; however, a specialized workshop is needed for repairs. It is advisable to clean the

strainer at least once a year, depending on the meter and water quality. When the meter no longer

functions well, it should be replaced or recalibrated. Water meters lose accuracy with time, and

about every five years a meter should be cleaned and recalibrated regardless of its status (defined

according to the nature of the water and the meter type). To recalibrate it, the meter should be

sent to a specialized workshop for inspection, repair and calibration. A water meter is oftenowned by the water users themselves, who guarantee that it is treated well. Even when the

external parts of a water meter belong to a water committee or project, the users may still be

responsible for the condition of the parts. A water committee will need to keep a stock of water

meters for replacing defective ones. To reduce costs, the number of different models should be

kept to a minimum.



1.4 Different methods of water distribution boosting water (mh)

1.4.1 Single booster system (h)

A water tank is placed in front of the pump system and filled with water from the mains. Thisallows the capacity of the mains to be lower than the building’s peak demand, ensuring constant

pressure even in peak flow situations. The break tank is filled with water during low

consumption periods and ensures a uniform water supply to the booster pumps at all times.

1.4.2

Zone-divided system (h)

The supply system is split into several zones supplying a maximum of 12 floors each. This

ensures adequate water pressure on all floors without using pressure relief valves. The minimum

pressure on the upper floor in each zone is kept at 1.5 - 2 bar. The maximum pressure on the

lowest floor in each zone does not exceed 4 - 4.5 bar.



1.4.3 Roof tanks ensure both water pressure and water supply in case of power failure (h)

This solution requires pressure reduction valves on each floor in order to avoid undesired high

static pressures at the tap, which creates unacceptable noise while tapping. In this model the

upper six floors require a separate booster system in order to create sufficient pressure. The static

pressure there is too low due to the insufficient geometric height to the roof tank.

1.4.4. Series-connected systems (h)

with intermediate break tanks draw on several other systems, utilising centrally-placed break

tanks to supply both the taps in its own boosting zone and all the zones above it.



With this system, a building is divided into smaller and more manageable pressure zones of 12

floors each. Every zone is then served by its own booster set. No pressure reduction valves are

required and in case of electrical breakdown the tanks will be able to supply pressure and water

for up to 12 hours. However, the tanks take up valuable space within the building, reducing the

room available for revenue generation.

1.4.5 A series-connected system operates on the same principles as the previous system, butwithout the intermediate break tanks (h)

This enables an effective usage of power because the water is only pumped to the zone where it

is used and not past it. However, complete control is very important. When a consumer draws

water on the upper floors, the booster systems must deliver the water from the bottom of the

building.

1.5 gravity and pressure distribution by storage tanks of individual buildings (mh)

1.5.1 Gravity distribution (h)

(a) Gravity distribution may be used in all instances, except where prohibited by § 73.43

(relating to pressurized distribution).

(b) The distribution system shall be arranged to provide for uniform distribution of the effluent.



(c) The flow shall be equally divided between individual laterals of a trench system or between

seepage beds by use of a distribution box.

(d) The flow shall be divided between individual laterals in a seepage bed by a distribution box

or by an unperforated pipe header connecting all laterals within the bed. Where distribution is via

an unperforated pipe header, the terminal ends of all individual laterals shall also be connected

with unperforated pipe.

(e) Distribution boxes shall comply with the following:

(1) When a distribution box is used, it shall be installed level to provide equal distribution of

treatment tank effluent to each line. For testing purposes, the person responsible for the

installation shall provide an adequate amount of water to check the level of the inlet and outlet

lines.

(2) Construction shall comply with the following:

(i) Distribution boxes shall have removable covers.

(ii) Each lateral shall be connected separately to the distribution box.

(iii) The bottom of all outlets shall be at the same elevation, and the bottom of the inlet shall

be at least 1 inch above the bottom of the outlet. The bottom of the outlet shall be at least 4

inches above the bottom of the distribution box.

(iv) Baffles shall comply with the following:

(A) A baffle shall be installed in the distribution box in the event that treatment tank

effluent is discharged to the distribution box by a pump or siphon.

(B) The baffle shall be perpendicular to the inlet, be secured to the bottom of the box and

extend vertically to a point level with the crown of the inlet pipe.

(v) A tee or elbow directed toward the bottom of the distribution box may be substituted for

the baffle required by subparagraph (iv).

(3) Distribution boxes shall be installed on an adequate base of undisturbed or properly

compacted earth or aggregate outside of the absorption area. Lightweight nonconcrete

distribution boxes shall be anchored or otherwise secured to prevent shifting after installation.

Adjustable distribution box weirs may be used on the outlet of the box.



(f) Laterals shall be a minimum of 3 inches in diameter unless a larger diameter is specified by

local plumbing or building codes. Bends used in the disposal field shall be made with standard

fittings.

(g) The maximum length of individual laterals employing gravity distribution is 100 feet.

1.5.2 Pressurized distribution (h)

Pressurized distribution is required in the following instances:

(1) All elevated sand mounds.

(2) When the percolation rate exceeds 60 minutes/inch.

(3) All systems having a total absorption area in excess of 2,500 square feet.

(4) Individual residential spray irrigation system spray fields and buried sand filters.

1.5.2.1 Pressurized distribution design (sh)

(a) General requirements are as follows:

(1) The piping used in a pressurized effluent system shall have watertight joints.

(2) Systems using pressure distribution shall meet the general requirements.

(3) Delivery pipes from dosing pumps shall be installed to facilitate drainage of the

distribution piping back to the dosing tank between doses.

(b) Seepage beds of 2,500 square feet or less shall meet the following design standards.

(1) Conveyance of effluent from the dosing tank to the absorption area shall be through a

delivery pipe sized to minimize friction loss. Check valves shall be prohibited on delivery pipes.

Where the system designer determines that water hammer may be a problem, thrust blocks may

be installed on delivery pipes.

(2) When equally sized absorption areas are dosed simultaneously, a header pipe shall be used

to connect the delivery pipe from the tank to the manifolds. The header pipe shall be sized to

minimize friction loss. Effluent application rates per square foot of absorption areas served by a

common header shall have a maximum design variation of 10%. If the distance from the

treatment tank to the absorption area would cause excessive backflow into the dosing tank, a

transfer tank may be used between the treatment tank or storage tank and dosing tank.



(3) Distribution of effluent to the individual laterals shall be by a central manifold extending

into the absorption area from the delivery pipe or header. The manifold shall have the following

minimum diameters:

Sq. ft. of Absorption Area Minimum Manifold Diameter

200 to 1,199 1 1/2"

1,200 to 2,500 2"

(4) Laterals shall be extended from both sides of the manifold by opposing tees or a double

sanitary tee.

(5) Laterals shall consist of 1 1/2 inch diameter pipe, with holes placed along the bottom of the

pipe; an end cap shall be cemented on the terminal end of the lateral. Minimum hole size shall be1/4 inch.

(6) The first hole in the lateral shall be 3 feet from the manifold. Additional holes shall be

placed 6 feet on center with the last hole placed directly in the end cap.

(7) The maximum length of a lateral from the manifold to the end cap shall be 51 feet and

contain nine holes.

(8) The location and spacing of the laterals shall conform to beds.

(9) Opposing laterals may not differ in length by more than 6 feet.

(10) When less than the maximum length of lateral is used, the lateral shall be shortened in 6-

foot sections with hole spacing maintained.

(11) All systems shall be designed to maintain a minimum of 3 feet of head at the terminal end

of each lateral.

(12) The minimum pump capacity (gpm) shall be calculated by multiplying the total number

of discharge holes contained in the laterals of a proposed distribution layout by the gpm factordetermined by the hole size at the design head level.

(13) Total pump head shall be calculated by addition of all losses incurred due to elevation

changes, pipe and fitting friction losses, and the head level to be maintained at the terminal end

of the lateral.



(14) For purposes of calculating head loss due to friction, head loss in the standard lateral shall

be assumed to be 0. Head loss due to friction in pipe and fittings used in construction of the

pressure system shall be calculated using a friction loss table for smooth-walled plastic pipe

(C=150).

(15) When siphons are used in a pressure distribution system, each discharge hole shall be at

least 5/16 inch in diameter. The discharge from all of the holes in the distribution system may not

be less than the minimum rate of the siphon and may not vary from the average discharge rate of

the siphon by more than 20%.

(c) Seepage beds of greater than 2,500 square feet shall meet the following design standards:

(1) The diameter of individual laterals, size and spacing of discharge holes, and minimum

diameter of the distribution manifold may not be restricted by subsection (b) except that no

discharge hole may be less than 1/4 inch for systems using pumps or 5/16 inch for systems using

siphons.

(2) The maximum length of a lateral designed under this subsection or subsection (d) shall be

100 feet.

(3) Discharge rates from the individual holes of the lateral at design head shall be calculated

using the sharp-edged discharge hole equation:

gpm=11.82(d2) gpm=gallons per minute

(d)=diameter of hole (inches)

(h)=head to be maintained at the terminal ends of the lateral (in feet).

(4) All piping and fittings in the system shall be sized to minimize friction losses to provide as

uniform distribution of effluent as possible.

(5) The design head at the terminal end of the last lateral shall be at least 3 feet.

(6) The head loss due to friction from the beginning of the distribution manifold to the

terminal end of the last lateral may not exceed 15% of the head level to be maintained at theterminal end of the lateral.

(7) Spacing of laterals and discharge holes in the laterals shall provide for uniform distribution

of the effluent over the seepage bed.



(8) The arrangement of laterals and discharge holes shall result in the discharge holes being

spaced at the apexes of either squares or equilateral triangles.

(i) The maximum spacing between discharge holes shall be 10 feet where an equilateral

triangle pattern is utilized.

(ii) The maximum spacing between discharge holes shall be 8 feet where a square pattern it

utilized.

(9) The minimum pump capacity shall equal the total discharge from all holes in the laterals

when operating at designed head.

(10) The permittee shall conduct a test pressurization of the completed distribution system in

the presence of the sewage enforcement officer prior to covering the piping system from view.

During the test, the permittee shall confirm that all joints are watertight and that a discharge is

occurring from each hole.

(d) Design of pressure distribution in trenches shall comply with the following:

(1) It applies to design of trenches utilizing pressurized effluent distribution.

(2) Variation in head in the laterals caused by differences in elevation or friction losses shall

be compensated for by individual design of the laterals.

(3) The effluent application rate per square foot of any two trenches served by a common

dosing tank shall have a maximum design variation of 10%.

(4) Equalization of loading may be accomplished by variation of discharge hole diameter

between trenches, variation of spacing of discharge holes between trenches or another method

approved by the Department or sewage enforcement officer.

(5) The maximum spacing between discharge holes is 10 feet.

(6) The manifold for a trench system shall be placed on undisturbed soil a minimum of 6

inches above the trench bottom.

(7) A minimum isolation distance of 3 feet shall be maintained between the manifold and the

beginning of any trench. The individual laterals in the trench shall be connected to the manifold

using unperforated pipe. The area beneath the manifold and connecting pipe shall consist of

undisturbed or compacted soil.

(8) The design head at the terminal end of each lateral shall be at least 3 feet.



1.6 System of water supply (mh)

1.6.1 Continuous ,their advantages and disadvantages Service connections, types and

sizes of pipes, water supply fixture and installations, special installation in

multistoried buildings (h)

Continuous flow systems provide an endless supply of hot water, so long as the electricity or gas

is available. Where continuous flow hot water systems are used Instantaneous or continuous flow

hot water systems are typically used:

• for outlets that are a long way from the main hot water storage system

• where hot water use is low and inconsistent, such as in a holiday home

• to boost hot water supply from systems that are not always able to meet demand (such as

heat pump water heaters or solar water heating)

• to boost hot water supply from limited storage systems or to fittings having high hot

water demand (e.g. showers).

1.6.1.1 How they operate (sh)

Continuous flow systems can be heated using electricity, gas or LPG. Although electric systems

are more energy-efficient than gas systems, gas has a higher maximum heating capacity and is

better able to impart sufficient heat to mains pressure water.

Operation of typical electric continuous flow water heater



Operation of typical gas continuous flow water heater

1.6.1.2 Advantages and disadvantages (sh)

Advantages of continuous flow systems over storage systems include:

• continuous hot water, i.e. supply does not run out

•

no requirement to keep water hot when not being used, so no standing losses and noenergy input to maintain the temperature of stored water

• no need for a cylinder, so useful where space is limited

• heat is to the required outlet temperature, without the need to heat it to 60ºC first

• easily adjustable temperature

• can be located close to the outlet

• gas units are usually fitted on an outside wall, saving interior space.

Disadvantages include:

•

both gas and electricity produce greenhouse gas emissions (electric units are responsiblefor emissions during generation, and gas units produce emissions during combustion)

• gas units have flue emissions

• limited water flow rates

• achievable flow rates are lower in colder areas

• electric systems may require heavy duty wiring

• electric systems cannot use off-peak electricity supply rates

• the pilot light on gas heaters can be extinguished by wind – electronic ignition is

recommended.

1.6.1.3 Calculating size (sh)

The required flow rate is used to size continuous flow systems, and this is based on the number

of outlets served by the unit. Obtain specific flow rates from the supplier or manufacturer.



Max. no. of outlets served

at one time

Flow rate

(litres per minute)

1 16

2 20

3+ 24

1.6.1.4 Connecting with other water heating systems (sh)

Continuous flow water heaters can operate in conjunction with hot water storage systems, to take

advantage of and overcome disadvantages of each system:

•

Example 1: Use a small volume hot water storage cylinder for the general hot watersupply and supplement with a continuous flow water heater from a cold water feed for

outlets with high hot water demand such as shower and washing machine. Mix hot water

at the outlet with the flow rate maximised from the continuous flow water heater and

minimised from the hot water storage cylinder.

• Example 2: Use the continuous flow water heater as a booster system to a storage system

with limited hot water capacity or intermittent energy supply (such as solar systems or

heat pumps). Requires specific plumbing arrangement.

1.6.1.5 Installation requirements (sh)

LPG and reticulated gas water heating systems are generally installed on the building exterior as

they require good ventilation for the exhaust gases. If the system is installed internally, the space

must be well ventilated and exhaust gases flued to the outside.

Electrical heaters are compact and can be installed close to the hot water outlet, often with

cabinetry.

1.6.2 intermittent, their advantages and disadvantages Service connections, types and

sizes of pipes, water supply fixture and installations, special installation inmultistoried buildings (h)

Intermittent water supply is when water is available to people from a piped water distribution

system for only a limited amount of time. This means that if you live in a place with intermittent

water supply and turn on a tap to get a glass of water, take a shower, or wash a dish, no water

will come out for many hours of the day or many days of the week.



Intermittent water supply may be defined as a piped water supply service that delivers water to

users for less than 24 hours in one day. It is a type of service that, although little found in

developed countries, is very common in developing countries. In an intermittent supply situation

the consumers secure their water supply through the use of ground or roof tanks, which are filled

during the time that the supply is provided. Intermittent water supply is enforced not only in

cases where there is water shortage, but also where the hydraulic capacity of a network is such

that it is not possible to satisfy demand, as well as in cases where the networks are severely

deteriorated.

The pressures that exist on water resources are highlighted by the water stress, which measures

the proportion of water withdrawal in relation to total renewable resources. As can be seen from

the map, a large proportion of the densely populated part of the planet has a high to very high

water stress indicator. It is therefore imperative to develop appropriate water management

approaches in order to manage our water resources efficiently and effectively.

Climate change adds to these concerns. It has been affecting the average weather patterns that we

were all used to and engineers and scientists have to take this into consideration in present and

future planning. As an example, in Cyprus, the largest island in the eastern Mediterranean, the

precipitation records of the last 100 years indicate an overall decrease in the mean annual

precipitation of about 15%, but annual variation in precipitation varies considerably from the

mean with long periods below average, affecting significantly the annual water resources of the

island. This pattern is very similar across the Mediterranean basin and there are cases in recent

years where cities were even forced to ship water from other countries in order to combat the

crisis. For instance, the town of Lemesos in Cyprus was supplied daily by tankers with waterfrom Athens in Greece for an eight month period in 2008/2009 to overcome a serious water

shortage problem caused by prolonged drought. During the same period Barcelona in Spain was

also being supplied water via tankers in order to relieve a similar water crisis. This phenomenon

seems to be growing to global dimensions.

Faced with such pressures, there is the prospect that water authorities will increasingly wish to

resort to delivering intermittent supplies. Usually during drought periods water authorities

impose water restrictions to both domestic and agricultural supplies. At the same time they move

forward with the construction of treatment units to treat domestic effluent for agriculture, and if

this measure is not sufficient they resort to the construction of desalination plants to produce

potable water for satisfying domestic needs, thus adding to the water balance and reducing

deficit. However, in most cases water authorities seem to overlook the obvious, which is to

manage the water networks in the most efficient and effective way in order to minimise losses.

1.6.2.1The contribution of water loss minimisation (sh)



Reducing losses from distribution networks is of the utmost importance and water utilities must

recognise this and respond positively. Efficient and effective water loss control should be

recognised as a first priority for improving potable water supply. Decision makers at all levels in

water utilities must understand that any water loss control strategy, in order to be effective, must

be a continuous activity based on a long-term strategy and should form an integral part of the

utility’s vision. The success of the strategy will inevitably depend on the commitment and

dedication at all levels within the utility and of course on the adoption of appropriate strategies

and techniques. A successful strategy is one that maintains the distribution network in a proper

working order, reducing and maintaining leakage at an economic level, and of course providing

the required level of service to all consumers.

1.6.2.2 The effects of intermittent supply (sh)

In this context, intermittent supply does not constitute an efficient and effective strategy for

managing distribution networks, irrespective of the problems and factors which lead to such amodus operandi. Intermittent supply may seem to be the ‘short’ term answer to water shortage

situations, but inevitably it has an adverse effect on the integrity of a water distribution network

and evidence is provided below to substantiate this based on real case studies.

In many instances there is no indication how long intermittent supply measures will be in place.

The hydrological conditions in each case could impact adversely on water supply for years, in

which case conserving limited water resources as much as possible may not be the long-term

solution, but it may be necessary to add to the water balance new unconventional water

resources. In many countries water shortage problems have been overcome through desalination

of brackish or saline water. Of course exploring every potential water source available may bethe only solution in many instances, but conservation is always one of the least expensive and

quickest solutions to ensuring that water will be available when needed.

Analysis of case study data has shown that there was a large increase in the number of reported

pipe breaks during periods of intermittent supply. In order to quantify this, a comparison was

made between the breaks reported before intermittent supply was applied and those reported

immediately after the measures were lifted.

Table Effect of intermittent supply on reported pipe bursts

Number of reportedbreaks Description

Before After % increase

Mains 1 in 7.14 km 1 in 2.38 km 300

Service connections 15.5 in 1000 29.7 in 1000 200



1.6.2.3 How does intermittent water supply work (sh)

Water distribution systems that supply water intermittently are designed and constructed for

continuous supply; however, in intermittent supply, pipes are empty for hours or days at a time.

Usually, a valve operator turns on and off a valve to supply water periodically. In many smaller

cities and towns with intermittent supply, the water utility will supply water to everyone at the

same time. In larger cities, they may supply it rotationally throughout the city; one family will

get water for two hours, their neighbors a few streets away will get water several hours later, and

families living on the other side of the city may get water the next day.

1.6.2.4 Where does this happen (sh)

Intermittent piped water supply is common in towns and cities in Asia, Africa, and Latin

America. While there is not much data about how common it is, the World Health

Organization/UNICEF Joint Monitoring Program, which tracks statistics related to water and

sanitation throughout the world, estimates that 90% of urban residents in South Asia and 30% in

each of Latin America and Africa have intermittent water supply (WHO and UNICEF, 2000).

The World Bank's International Benchmarking Networking , which collects data on water

utilities, report that 84% of reporting utilities in low-income and 14% in middle-income

countries supply for fewer than 24 hours of the day (van den Berg and Danilenko, 2011). India

has some of the fewest hours of supply in the world: no major city in India has continuous water

supply, and most report an availability of 4 hours per day (McKenzie and Ray, 2009).

1.6.2.5

Why is intermittent supply a problem (sh)

Intermittent supply creates problems for both the water utility and households who need to use

the water. Since water is not always available, households must store water between delivery

times. The amount they need to store depends on the number of people in the house, the amount

of water they require, and time until water will be delivered again. A family of 6 using 50

liters/person/day (intermediate water access, defined by the World Health Organization (Howard

and Bartram, 2003)) would need to store 300 liters (80 gallons) water for a day. A larger

household of 10 people that receives water every five days would need to store at least 2500

liters (660 gallons). If households cannot store that much water, or they run out of water, they

may need to turn to other water sources, such as groundwater, which in a city is likely polluted,

or pay a much higher cost for vended or tanker truck water. The extra costs that households must pay to cope with unreliable access to water – storage containers, alternative sources, pumping

costs, labor - are known as coping costs, and often add up to more than the amount they pay to

the utility for the water . Intermittent supply can also create problems for the water utilities, as it

is difficult to track where the water is going (and therefore track down and fix leaks in the

distribution system) and to collect payments from consumers who may be unhappy with



(i) The surface area of a filter tank shall be a minimum of 40 square feet for systems using

an aerobic treatment tank and serving a single family residence of three bedrooms or less. The

filter area shall be increased by 10 square feet for each additional bedroom over three.

(ii) Systems proposing the use of a septic tank to serve a single family dwelling of three

bedrooms or less shall be designed using two filter tanks or a single tank with two chambers.

Each tank or chamber shall have a surface area of 40 square feet. The filter area of each filter

shall be increased by 10 square feet for each additional bedroom over three.

(iii) Tanks shall be watertight and made of a sound, durable material which is not subject to

excessive corrosion or decay.

(iv) Concrete tanks shall have a minimum wall thickness of 2 1/2 inches and be adequately

reinforced.

(v) If precast slabs are used as tank tops to support the access covers, the slabs shall have a

thickness of at least 3 inches and be adequately reinforced.

(vi) Tanks shall be designed and constructed so that the depth from the cover to the top of

the sand layer provides sufficient freeboard to allow for maintenance of the sand surface.

(vii) Access shall be provided by a minimum of two access openings. These access openings

shall be a minimum of 36 inches by 36 inches and provide access to the entire surface of the

filter.

(viii) The tank wall shall be extended a minimum of 6 inches above final grade.

(ix) Access covers shall be insulated against severe weather, secured by bolts or locking

mechanisms, prevent water infiltration and the entrance of debris, and be lightweight to facilitate

routine maintenance.

(2) Media. Sand suppliers shall provide certification, in writing to the sewage enforcement

officer and permittee, with the first delivery to the job site, that the sand to be supplied meets the

following specifications:

(i) The fine aggregate shall have an effective size of between 0.3 to 0.6 mm, a uniformity

coefficient of less than 3.5 and less than 4% of the coarse aggregate passing the #100 sieve. The

sieve analysis shall be conducted in accordance with Department of Transportation PTM #616

and the uniformity coefficient shall be determined by using Department of Transportation PTM

#149.



(ii) The sand may not contain more than 15% by weight deleterious material as determined

by Department of Transportation PTM #510.

(3) Contents of certification. The written certification shall include the name of the supplier,

the testing results, the testing date, the amount of material purchased under this certification and

the delivery date.

(4) Construction. The sand filter shall be constructed according to the following standards:

(i) A 4-inch diameter perforated underdrain pipe with a minimum 2,500 pound crush test

specification shall be placed on the bottom of the tank.

(ii) Two rows of perforations between 1/2 to 3/4 inch in diameter shall be drilled in the

underdrain pipe at 6 inch intervals and the pipe shall be placed so the perforations face

downward and the rows are approximately 45° from each other.

(iii) Aggregate shall be placed around the underdrain to a total depth of 5 inches from the

bottom of the tank. Coarse aggregate used in the underdrains and distribution system shall meet

the Type B requirements posted in the Department of Transportation specifications Publication

#408, section 703, Table B and uniform size and grading of the aggregate shall meet AASHTO

No. 57 requirements.

(iv) Minimum depth of 4 inches of aggregate shall be placed over the aggregate underdrawn

material. Coarse aggregate used in the transition layer shall meet the Type B requirements.

(v) Sand shall be placed over the aggregate to a depth of at least 24 inches.

(vi) The sand in the filter may not be greater than 36 inches deep.

(vii) The central distribution system shall be designed and installed to convey a minimum 2

inch flood dose of effluent to the surface of the sand filter. A high water alarm shall be installed

in the filter tank which produces an audible and visual alarm when effluent backs up on the filter

surface to 12 inches above the surface of the sand.

(viii) When two filters or chambers are required to treat septic tank effluent, the duplicate

units shall, at the discretion of the designer, be flooded alternately, periodically by using valves,

or simultaneously.

(ix) The central distribution piping may not be more than 2 inches in diameter.

(x) The height of the central distribution system’s effluent outlet above the sand surface shall

allow for the installation of a splash plate and the maximum flooding depth of the sand filter.



(xi) A concrete splash plate or other suitable material shall be located under each effluent

outlet to prevent scouring of the sand surface. Movement of the splash plate during the flooding

operation shall be prevented.

(c) Buried sand filters shall meet the following standards:

(1) Location.

(i) When buried sand filters are proposed to be installed in areas where bedrock is

encountered above the proposed depth of the sand filter, or where the seasonal high groundwater

table rises above the proposed depth of the sand filter, the designer should consider measures to

prevent filter and liner damage and groundwater infiltration.

(ii) A buried sand filter may not be constructed in unstabilized fill.

(2) Size.

(i) The size of the sand filter shall be determined on the basis of the appropriate application

rate and the estimated daily sewage flow in accordance with (a) (relating to absorption area

requirements) but the sand filter area shall be at least 300 square feet for use with either an

aerobic treatment tank or septic tank with solids retainers units.

(ii) For a single family residence, the minimum sand filter area shall be based on a maximum

hydraulic loading of 1.15 square feet per gallon per day.

(iii) Where aerobic treatment precedes the sand filter, a 1/3 reduction to the filter area may be used to size the filter.

(3) Media.

(i) At least 2 inches of clean aggregate meeting subsection (b)(4)(iii) shall surround under

drains and distribution pipes. A minimum of 4 inches of aggregate meeting subsection (b)(4)(iv)

shall be placed over the underdrain. A layer of porous geotextile material may be placed on top

of both layers of aggregate to prevent migration of soil or sand into the aggregate.

(ii) At least 24 inches of clean sand shall be placed over the underdrawn aggregate. The sandshall meet the specifications.

(iii) The minimum depth of earth cover over the coarse aggregate in all installations shall be

12 inches. When the top of the aggregate is less than 12 inches from the undisturbed soil surface,

the soil cover shall extend beyond the filter area by at least 3 feet on all sides. The soil over the



sand filter shall be so graded that surface water will run off, consist of soil suitable for the

growth of vegetation and be seeded to control erosion.

(4) Underdrain piping.

(i) Underdrain piping shall be laid on a grade of 3 to 6 inches per 100 feet sloped to theoutfall pipe.

(ii) Underdrain piping shall be positioned between the distribution laterals to maximize

effluent travel through the filter sand.

(iii) Underdrain piping holes shall be equal or greater in number and size to the distribution

piping holes.

(iv) Underdrain piping shall have two rows of holes placed at approximately 45° angle from

each other along the bottom half of the pipe.

(v) The outfall pipe from the Underdrain header shall have an antiseep collar and bentonite

clay plug or a leak proof boot sealed as per manufacturer’s instructions to the subsurface sand

filter liner.

(5) Filter base and liner. The base of the filter shall be sloped to the underdrain pipe a

maximum of 1%. An impervious liner of hyplon, polyvinyl chloride or polyethylene sheeting of

20 millimeter thickness or equal shall be installed on a tamped earth base to prevent seepage to

the groundwater. A concrete bottom and sides may also be used at the discretion of the designer.

A 2-inch layer of sand or a layer of 10 ounce porous geotextile material shall be provided on

each side of the liner to prevent punctures and tears. Seams shall be made according to

manufacturer’s specifications.

Review Questions

1. Explain Demand of water for domestic, commercial, industrial and public utility purposes

as per BIS standards.

2.

Define Per capita demand, leakage and wastage of water and its preventive measures.

3. Explain different types of Storage and Distribution of Water.

4. What are Different methods of water distribution boosting water?

5. Describe gravity and pressure distribution by storage tanks of individual buildings.

6. Explain System of water supply.



7. Describe intermittent, their advantages and disadvantages Service connections, types and

sizes of pipes, water supply fixture and installations, special installation in multistoried

buildings.



Chapter-2

DRAINAGE (ch)

Structure of this unitDrainage, sewers, chamber, fixtures

Learning Objectives1. Principles of drainage

2. surface drainage combined and separate system of drainage

3. shape and sizes of drains and sewers

4.

storm water over flow chambers

5. methods of laying and construction of sewers

6. House drainage: traps – shapes, sizes, types, materials and function

7.

Inspection chambers: sizes and construction8. Ventilation of house drainage

9. Types of fixtures and materials

2.1 Principles of drainage (mh)

Some of the basic principles of drainage design are briefly outlined below:

• The surface runoff over the pavement surface and the shoulders should be drained away

as quickly as possible, preventing the water from finding entry into the pavement layers

from the top and into the subgrade from the top and the sides.

• Precipitation over the open land adjoining the road should be led away from the

pavement structure through natural drainage channels or artificial drains. Suitable cross-

drainage channels should be provided to lead the water across the road embankment

which may be cutting across to the natural drainage courses.

• Consideration should be given to deal with the precipitation on the embankment and cut

slopes so that erosion is not caused.

• Seepage and subsurface water is detrimental to the stability of cut slopes and bearing

capacity of subgrades. An effective system of subsurface drainage is a guarantee against

such failures.• Landslide-prone zones deserve special investigations for improving drainage.

• Relatively poor embankment soils can perform satisfactorily if drainage is considered in

the design.

• Water-logged and flood-prone zones demand detailed consideration for improving the

overall drainage pattern of the area through which the road is aligned.



2.1.1 Provision of Surface Drainage (h)

For an effective surface drainage system, it must be ensured that the following measures are

taken on all PMGSY roads:

a.

Cross-slope or camber on the carriageway must be ensured by means of a Camber Board

at all times to conform to the standards laid down in the Rural Roads Manual. The cross-

slope of the shoulder should be 1% steeper than the cross-slope of the carriageway,

subject to a minimum of 4%.

b. Longitudinal drainage should also be ensured, despite the provision of adequate cross-

slopes, for better internal drainage of pavement layers, especially granular materials and

in cut sections. Similarly along vertical curves, the drainage considerations are of great

importance and in some cases, the length of the vertical curve may have to be adjusted to

satisfy drainage requirements. For most conditions, a minimum 0.3% longitudinal

gradient is considered adequate.c. It is absolutely essential to provide roadside drains/ ditches to collect the surface water

from the roadway (and lead it to an identified outlet) and also to drain the base of the

roadway to prevent saturation and loss of support for traffic.

Roadside drains/ ditches should be constructed and maintained in accordance with the following:

provide enough area to accommodate storm flow and depth enough to drain the

base course.

protect the surface of ditches from erosion with turf cover or other suitable lining.

keep velocities low enough to prevent erosion but great enough to preventdeposition or silting.

maintain a continuous and unobstructed waterway.

provide stable outlets to natural channels or drainage ditches.

The design of the roadside drains/ ditches can be done in the following step-by-step manner (the

needed formulae, design tables and charts etc are available in the Rural Roads Manual) :

From the known soil type, arrive at the value of Manning’s Rugosity coefficient,

side slopes and the maximum permissible velocity.

Determine the slope from the topography. For the given discharge, calculate the hydraulic mean depth from Manning’s

formula.

Operations Manual for Rural Roads Find out the cross-sectional area from the

given discharge and the maximum permissible velocity.

Calculate the critical depth and determine whether the flow is tranquil or

turbulent. If it is tranquil, add a freeboard to the depth and finalise the cross-



section. If the flow is turbulent, it may be necessary to line the channel or

decrease the longitudinal slope.

In the absence of any data, the salient design features are given in the Rural Roads Manual,

reproduced below

Location : 300 mm deeper than the bottom of road crust

Minimum width at bottom : 450 mm

Minimum longitudinal grade : 0.5 percent

Discharge : 0.50 cum per sec.

Shape : Triangular, Rectangular and Trapezoidal

Side slope : Generally not exceeding 1 in 4



d. Lining : Grass lining is more economical than other linings to establish and with proper

maintenance, will indefinitely provide adequate protection against erosion for most of the

site situations. A key factor to the success of grass lining is that it must form a firm, dense

turf. For a rapid establishment of vegetal lining in ditches, the same principles must be

followed as adopted for providing vegetal protection cover on slopes. The roadside drain/

ditch can also be lined with sod freshly cut, to a depth of about 20 mm from a well

established dense turf. Sod strips should be placed across the ditch rather than lengthwise.

The joints should be staggered and strips pressed firmly against one another. After the

sod is in place, it is tamped or rolled to produce a smooth continuous surface. It should be

watered for several weeks after placing, as conditions may warrant.

e.

Outlets : At points of outlet to natural waterways or drainage channels, ditch erosion can

occur unless appropriate steps are taken to avoid it. It is necessary, therefore, to provide a

well-protected sluice or chute to carry water from the ditch level to the stream or to build

an outlet structure. A sluice is generally more suitable and economical to construct than

an outlet structure. The grade should be as flat as possible (less than 10 percent).

Generally, there is substantial drop from the ditch to collecting channel and it is

necessary to divert the sluice sufficiently away from the road as it drops to the stream to

meet the grade requirement.

From one side of the road where there is no natural outlet, cross-overs of concrete ormetal pipe may be installed to drain water to the other side with a natural outlet. It must

be ensured at all times that the outlet while discharging water into the natural stream is

always kept higher than the free water level in the natural water course or, in other words,

the outlet must never be submerged.

2.1.2 Slope Protection Against Erosion (h)

The following principles need to be followed for providing slope protection against surfaceerosion.

• Keep slopes flat and edges well rounded to reduce erosion potential to a minimum.

• Establish a healthy, vegetal cover as quickly as possible.

• Intercept water from higher ground before it reaches slopes susceptible to erosion.

• Provide safe outlets for water collected in intercepting drains and gutters.



• Absorption of water in the filler material, which may not be fully non-plastic, may

seriously undermine the load support characteristics of the layer.

• Free water in bituminous pavements results in stripping of the binder leading to faster

cracking and deterioration.

Condition of subsurface water accumulation arises due to one or more of the following:

•

Top, i.e., surface infiltration of precipitation through paved or unpaved areas, shoulders,

higher adjoining grounds/hills seeps down. Collection of water in pot holes, undulations,

cracks, defects, joints also seeps down.

• Lateral seepage through shoulders, adjoining hill slopes etc.

• Free water from a high water table or capillary action from a water table.

Best way of drainage of pavement course is to provide and extend a specially designed subbase

layer, called drainage layer, upto the embankment slope face. The drainage layer also helps in

draining away the water from a high water table and also acts as a capillary cut off and thus

prevents damage to subgrade and subbase layers. In addition, proper cross fall to the drainagelayer is required to be provided to guard against sluggish flow.

In cases where it is not possible to take the drainage layer upto the embankment slope face

provision of subbase drainage is achieved through sub surface drain pipes encased in drainage

media. Guidance for design of subsurface drains may be taken from Para 8 (Sub Surface

Drainage) of IRC SP:50-1999-Guidelines on Urban Drainage. Sub surface drains are also

required where quantity of subsurface water is very high which can not be drained off fully using

economical thickness of drainage layer.

A typical subsurface drain intercepting free water in a slope before it reaches to a point as wouldrender the slope unstable

.



2.2 surface drainage combined and separate system of drainage (mh)

2.2.1 Surface drainage systems (h)

The regular surface drainage systems, which start functioning as soon as there is an excess of

rainfall or irrigation, operate entirely by gravity. They consist of reshaped or reformed land

surfaces and can be divided into:

•

Bedded systems, used in flat lands for crops other than rice;• Graded systems, used in sloping land for crops other than rice.

The bedded and graded systems may have ridges and furrows.

The checked surface drainage systems consist of check gates placed in the embankments

surrounding flat basins, such as those used for rice fields in flat lands. These fields are usually

submerged and only need to be drained on certain occasions (e.g. at harvest time). Checked



surface drainage systems are also found in terraced lands used for rice.

In literature, not much information can be found on the relations between the various regular

surface field drainage systems, the reduction in the degree of waterlogging, and the agricultural

or environmental effects. It is therefore difficult to develop sound agricultural criteria for the

regular surface field drainage systems. Most of the known criteria for these systems concern the

efficiency of the techniques of land leveling and earthmoving.

Similarly, agricultural criteria for checked surface drainage systems are not very well known.

2.2.2 Subsurface drainage systems (h)

Mug and sole drain (Scotland, 18th century)

Like the surface field drainage systems, the subsurface field drainage systems can also be

differentiated in regular systems and checked (controlled) systems.

2.2.3 Controlled drainage system (h)

When the drain discharge takes place entirely by gravity, both types of subsurface systems have

much in common, except that the checked systems have control gates that can be opened and



Modern buried pipe drains often consist of corrugated, flexible, and perforated plastic (PE or

PVC) pipe lines wrapped with an envelope or filter material to improve the permeability around

the pipes and to prevent entry of soil particles, which is especially important in fine sandy and

silty soils. The surround may consist of synthetic fibre (geotextile).

The field drains (or laterals) discharge their water into the collector or main system either by

gravity or by pumping.

The wells (which may be open dug wells or tubewells) have normally to be pumped, but

sometimes they are connected to drains for discharge by gravity.

Subsurface drainage by wells is often referred to as vertical drainage, and drainage by channels

as horizontal drainage, but it is more clear to speak of "field drainage by wells" and "field

drainage by ditches or pipes" respectively.

In some instances, subsurface drainage can be achieved simply by breaking up slowly permeable

soil layers by deep plowing ( sub-soiling), provided that the underground has sufficient natural

drainage. In other instances, a combination of sub-soiling and subsurface drains may solve the

problem.

2.3 shape and sizes of drains and sewers (mh)

Sewers with the most varying cross sections and dimensions have been used since the beginning

of modern sewage technology and some are still in use to this day.

The most important cross-sectional shapes are the circular, the normal ovoid and the normal arch

cross section.

The circular cross section was and still is preferred in use because of its structural and hydraulic

advantages in the nominal size range 100 ≤ DN/ID ≤ 500.

Since the development of reinforced and pre-stressed concrete technology, the progressive

improvement of pipe manufacturing and pipe making, pre-finished pipes in circular cross section

even up to DN 4000 have been used for main collectors.

DN is the abbreviation for nominal size. It is a characteristic size for circular cross sections

measured in mm but without the explicit indication of the mm unit. It approximately corresponds

to the internal diameter.

The normal ovoid cross section was used for the first time in 1846 in London and arrived in

Germany about 1870 [Frühl10].



Hydraulically, it has particular advantages in the drainage of larger, erratic drain flows, e.g. for

combined water sewers with small dry-weather flows.

Together with the arch cross section, it is designated by the axial dimensions of width (b) /height

(h) in the millimetre sizes but without indication of the mm unit.

Ovoid cross sections have, and are still being used in the upside down position in order to lower

the water level line, to improve the static effects or to make accessibility easier.

In the past years, this sewer cross section has experienced a renaissance because of its static and

operational advantages as well as the reduced danger of depositing due to lower velocities.

Connected with this are reduced waste emissions in wet weather and better handling of larger

waste quantities in the sewage treatment plant in dry weather.

Arch cross sections offer advantages for larger flows and restricted construction height.

Although the hydraulic efficiency for partial filling is poor, yet the shape is statically

advantageous because it approximates the course of the line of pressure.

In particular cases, e.g. in the building of holding sewers, rain holding basins or for defined

location collecting points, rectangular cross sections with clear axial dimensions of about 800

mm have been, and are still used. The bottom is sloped laterally.

Besides these regular cross sections, there is a further range of cross-sectional shapes and sizes,

which were also standardised in the past and are still used in individual cases

2.4 storm water over flow chambers (mh)

Overflow chambers are structures installed in sewer systems used separation of storm water or,

as applicable, wastewater in unified sewer systems. Both by their hydro-engineering design as

well as builder’s works in connection, overflow chambers belong to the most complicated

structures in sewer systems. Therefore, you will find in our offer pre-fab type range ofoverflow chambers, which may bring partial solutions to these problems.

2.4.1 AS-ŠOK (h)



Overflow slot chambers are especially advantageous for low-gradient terrain configurations that

frequently face the problem of backwater in the incoming sewer, with the overflow sewer

leading to a recipient. In general, the slot chambers guarantee minimal exceeding of the outflow

Qt towards the wastewater treatment plant, so long as the total inflow Qc at the chamber does not

exceed 10 to 12 times the limit flow value Ql.

ADVANTAGES

• High operational reliability

• Minimal problems with sludge settlement

• Capturing a substantial amount of pollution from the first flush

• No backwater is caused in the incoming sewer

• Possibility to control the required flow Ql



OVERFLOW CHAMBERS OF THE AS-ŠOK RANGE

Type

L B H* hv D d* z* s** WeightConcrete

volume

[mm] [mm] [mm] [mm] [mm] [mm] [mm] [mm] [kg] [m3]

AS–ŠOK400

2 400 1 300 2 500 600300

300 50075

860 3,9

400 100

AS–ŠOK 3 400 1 300 2 700 800 500 400 700 125 1 150 6,0



600 600 150

AS–ŠOK800

4 600 1 300 2 700 900 800 400 800 200 1 580 10,4

AS–ŠOK1000

5 400 1 800 2 900 1 100 1 000 500 1 000 250 2 120 16,3

AS–ŠOK1200

6 550 1 800 2 900 1 300 1 200 600 1 200 300 2 690 18,3

* Maximum values for the particular size type, ** Recommended values for the particular size

type

2.4.2 AS-BALOK (h)

Overflow chambers are especially useful in cases when pipeline retention in the incoming sewer

can be used to advantage. The AS-BALOK type is based on the principle of the separation of

diluted wastewater over an overflow edge. Every type of these chambers is equipped with an

integrated slide valve at the outflow to the throttle line, with an adjustable overflow edge. Both

these control elements are made of stainless steel 17 240. The minimum limit outflow Ql from

the chamber is limited by the control range (DN 150 limits the flow to approx. 15–20 l/s).



ADVANTAGES

• Reliable separation of rainwater

• Adjustable height of the overflow edge

• Control of the required flow Ql

•

Possibility to change direction right in the chamber

OVERFLOW CHAMBERS OF THE AS-BALOK RANGE

Type

L B H* hv ho1 ho2 D WeightConcrete

volume

[mm] [mm] [mm] [mm] [mm] [mm] [mm] [kg] [m3]

AS–BALOKO/400

3 400 1 300 2 400 425 425 200300,

400880 4,9

AS–BALOKO/600

4 700 1 800 2 400 450 410 200500,

6001 340 8,6

AS–BALOKO/800

5 700 2 470 2 500 450 400 200 800 1 880 14,0

AS-BALOK K/600

- 2 470 2 300 450 425 200

300,

400

500,

600

920 4,8

AS-BALOK K/800

- 3 670 2 300 450 415 200 800 1 520 8,8

* Standardized structure height (can be adjusted if necessary)

2.5 methods of laying and construction of sewers (mh)

Good construction of a simplified sewer network is essential as poor construction inevitably

leads to major operational problems, and even to system failure (Watson, 1995). Good practice is

similar to that used for conventional sewerage, but special care has to be given to laying small



diameter sewers at shallow gradients. Good construction supervision is essential (lack of

supervision generally leads to poor construction) but difficult to guarantee. One option that

should be carefully considered is the training of small contracting companies inexperienced in

simplified sewer construction. This is likely to be extremely beneficial – such training, combined

with construction supervision, is probably the best way to ensure good construction.

2.5.1 Sewer gradient and ground slope (h)

The slope of the ground surface (S , m/m) may be (a) less than, (b) equal to, (c) greater than, or

(d) much greater than, the minimum sewer gradient ( I min, m/m) calculated from equation.

Furthermore, the depth to the invert of the upstream end of the length of sewer under

consideration may be (a) equal to, or (b) greater than, the minimum depth permitted (hmin, m),

which is given by:

hmin = C + D

where C = minimum required cover, m

D = sewer diameter, m

Minimum values of C used in Brazil are 20 cm for in-block sewers and those laid in front

gardens, and 40 cm for those laid in pavements (sidewalks). Tayler (1996) recommends

minimum values of C between 25 and 50 cm for concrete pipes laid in lanes and roads with 100

mm gravel or brick ballast bedding.

There are six combinations of sewer gradient and ground slope that are likely to be

encountered in practice. These are:



Case 1. S < Imin and the invert depth of the upstream end of the sewer (h1, m) > hmin: choose i

= I min and calculate the invert depth of the downstream end of the sewer (h2, m) as:

h2 = h1 + ( I min – S ) L

where L = length of sewer under consideration, m.

Case 2. S = I min and h1 >>hmin: choose i = I min and h2 = h1.

Case 3. S > I min and h1 = hmin: choose i = S and h2 = h1.

Case 4. S > I min and h1 > hmin: choose h2 = hmin and calculate the sewer gradient from:

i = S + (hmin – h1)/ L subject to i >> I min.

Case 5. S > I min and h1 > hmin: as Case 4, but an alternative solution is to choose i = I min and

calculate h2 from equation 5.2. The choice between these alternative solutions is made on the

basis of minimum excavation.

Case 6. S >> I min and h1 >>hmin: here, it is usually sensible to divide L into two or more

substretches with h2 = hmin and i << S (but obviously I min) in order to minimize excavation. A

drop manhole is placed at the substretch junction.

2.5.2 Grease/grit traps (h)

If the kitchen wastewater contains an appreciable amount of fat and grease, it is desirable that a

small individual household grease trap is installed to intercept the kitchen wastewater before it is

discharged into the sewer. In Brasília Sarmento (2000) found grease traps functioning well in 90 percent of households in the medium to low-income area of Vila Planalto. However, in general

user education may be necessary to ensure people understand their operation and maintenance.

A related problem is that many householders drain water from yards and roofs to the sewer. This

practice should be discouraged whenever possible, but it is difficult to avoid completely in areas

where there are no alternative storm drainage facilities. Householders should be encouraged to

provide a simple gully trap on their property to both attenuate flows to the sewer and catch grit

before it enters the sewer. This should ideally be located on a drain carrying only storm water

and certainly upstream of the junction with the pipe from the WC. The trap should be built with

open-jointed brickwork so that stormwater can percolate away. The base may be earth, no-fines

concrete or sand-grouted brickwork, again to increase percolation.

Experience often suggests that people are often unaware of the importance of these traps and an

effective campaign of user education will be necessary to ensure that they are cleaned at regular

intervals. Of the two, the gully/grit trap will probably be of greater importance in ensuring that



the sewer operates effectively, except where the sewer connection is from a restaurant or some

other business that generates large quantities of grease.



2.5.3 Sewer pipe materials (h)

Hydrogen sulphide generation in simplified sewers can be expected to occur, and thus concrete

and asbestos-cement should not be used as they will be corroded by the H2S generated. In

practice, therefore, plastic (normally PVC) or vitrified clay pipes should be used. Where

possible, plastic pipes are to be preferred as they come in longer lengths and are more easily

jointed properly, so that infiltration (i.e. groundwater ingress) is minimised.

2.5.4 Sewer appurtenances (h)

The important point to remember when considering the details of sewer appurtenances is that

standards and design details should be related to location and function. Where condominial

systems are laid at shallow depths, large expensive manholes can be replaced by simpler

inspection chambers or junction boxes. These can be rectangular or circular in shape. Figure

shows a simple brick inspection chamber as used in Brazil. The Orangi Pilot Project in Pakistanhas developed a system based on the use of cast-in-situ cylindrical concrete chambers. Another

option is to use pre-cast cylindrical concrete sections. A more recent development is the all-

plastic unit, which is manufactured by Tigre S.A., Joinvile, Brazil.1 Junction chambers are

normally provided at every connection to the sewer, and inspection chambers at changes in

direction and at intervals of no more than 30 m for condominial sewers and 100 m for public

collector sewers. At changes of sewer diameter the sewers should be aligned invent to invert in

junction/inspection chambers (other than at drop junctions).

2.6 House drainage: traps – shapes, sizes, types, materials and function (mh)

In plumbing, a trap is a U-, S-, or J-shaped pipe located below or within a plumbing fixture. An

S-shaped trap is also known as the S-bend invented by Alexander Cummings in 1775 but

became known as the U-bend following the introduction of the U-shaped trap by Thomas

Crapper in 1880. The new U-bend could not jam, so, unlike the S-bend, it did not need an

overflow. The bend is used to prevent sewer gases from entering buildings. In refinery

applications, it also prevents hydrocarbons and other dangerous gases from escaping outside

through drains.

The most common of these traps in houses is referred to as a P-trap. It is the addition of a 90

degree fitting on the outlet side of a U-bend, thereby creating a P-like shape. It can also be

referred to as a sink trap due to the fact it is installed under most house sinks.

Because of its shape, the trap retains a small amount of water after the fixture's use. This water in

the trap creates a seal that prevents sewer gas from passing from the drain pipes back into the



occupied space of the building. Essentially all plumbing fixtures including sinks, bathtubs, and

toilets must be equipped with either an internal or external trap.

Because it is a localized low-point in the plumbing, sink traps also tend to capture heavy objects

(such as jewelry) that are inadvertently dropped into the sink. Traps also tend to collect hair,

sand, and other debris and limit the ultimate size of objects that will pass on into the rest of the

plumbing, thereby catching over-sized objects. For all of these reasons, most traps can either be

disassembled for cleaning or they provide some sort of cleanout feature.

Gully traps

Gully traps receive discharge from wastewater fixtures. One gully trap may receive discharge

pipes from several outlets.

Each residential building must have at least one gully trap. If a drainage system becomes

blocked, the gully trap provides the point where sewage can overflow outside the building,

instead of building up inside the pipe and overflowing inside the building.

Gully traps must:

• have an overflow rim at least 150 mm below the overflow level of the lowest fixture

served by the system

• be located within the legal boundary of the land on which the building stands

• prevent surface water from entering the trap

•

be constructed so the grate will lift to allow surcharge

• have at least one discharge pipe feeding into it to maintain the water seal.



Gully trap construction

Gully trap dimensions and requirements

A floor waste gully acts as a floor drain as well as receiving the discharge from wastewater

fixtures. It may only receive discharge pipes from wastewater fixtures that are located in the

same room. It may also be used as a shower outlet but cannot receive solid waste, for example,

from a WC pan.

The advantage of using a floor waste gully is that it reduces the number of connections required

to the drain and the length of pipe.

They may be used in buildings where overflowing water could enter another property.

Floor waste gully trap



2.6.1 Ventilation of drains (h)

Drainage systems must be ventilated to reduce the build-up of foul air within the drains. A

discharge stack that is within 10 m of the head of the drain may be used as the drain vent pipe.

Ventilation requirements include:

• every drain must be ventilated by an 80 mm diameter minimum vent pipe which

terminates to open air

• every branch drain over 10 m in length must be ventilated

• vent pipes must be located so that there is less than 10 m of upstream drain

• vent pipes must be located downstream of the discharge pipe that is closest to the head of

the drain – to allow for regular flushing at the point where the vent connects with the

drain.

Main drain venting

Branch drain venting

Pipe sizing and gradient

Pipe gradients are expressed as a ratio of the pipe length and the amount of fall over the length.

The amount of fall is usually expressed as 1, for example, if a pipe gradient is 1:100, it has a fall

of 1.0 m over 100 m of length.



Pipe gradient

The minimum diameter for a drain is 100 mm, except where it carries discharge from wastewater

fixtures only, in which case, it may have a minimum diameter of 80 mm.

Calculating larger diameters, the size and gradient of a drain is based on the total of all dischargeunits that each section of the pipe carries. Each fixture type is given a rating derived from its

expected discharge:

• 1:20 for 32 mm pipes

• 1:40 for pipes 65 mm diameter and under

• 1:60 for pipes 100 mm diameter and under

Drains must be laid:

•

at even grades• so the diameter does not decrease in the direction of flow

• with a minimum diameter and gradient as set out in G13/AS2:Table 2 Drain discharge

loading and minimum gradients.

Materials for drains

Materials and standards for drainage pipes are given in G13/AS2:Table 1.

Drainage pipes must have flexible joints so that pipes are not damaged by differential settlement.

The material with which a pipe is manufactured often forms as the basis for choosing any pipe.Materials that are used for manufacturing pipes include:

• Carbon Steel (CS)

• Low Temperature Service Carbon Steel (LTCS)

• Stainless Steel (SS)

• Non-Ferrous Metals (Inconel, Incoloy, Cupro-nickel etc.)



• Non-Metallic (ABS, GRE, PVC, HDPE, tempered glass, etc. )

• Chrome-molybdenum steel (Alloy steel) — Generally used for high temperature service

The bodies of fittings for pipe and tubing are most often of the same base material as the pipe or

tubing being connected, for example, copper, steel, polyvinyl chloride (PVC), chlorinated

polyvinyl chloride (CPVC), or acrylonitrile butadiene styrene (ABS). However, any material that

is allowed by the plumbing, health, or building code (as applicable) may be used, but must be

compatible with the other materials in the system, the fluids being transported, and the

temperatures and pressures inside and outside of the system. For example, brass- or bronze-

bodied fittings are common in otherwise copper piping and plumbing systems. Fire hazards,

earthquake resistance, and other factors also influence choice of fitting materials.

Testing of drains

Drains must not be covered over until they have been inspected and tested for leaks.

Depending on the type of drain and the situation, tests that may be applied to a drain to test the

joint performance include:

• water test

• smoke test

• coloured water test

• low-pressure air test.

2.7 Inspection chambers: sizes and construction (mh)

An Inspection Chamber is a clean-out generally installed at the property line of a building. It

allows the municipality or city to access the sanitary or storm sewers without disturbing the

building owner. The municipality or city can service the laterals to the building with cleaning

equipment for blockages or they can camera the lateral for inspection purposes. An Inspection

Chamber installed at the property line can indicate whether the blockage is on the building

owner’s side or the city/municipality’s side and whose responsibility it is for cleaning. Inspection

Chambers can also be used for ‘sampling’ what is going through the lateral should the need arise

to take samples. The Mainline Adapt-a-Valve Inspection Chamber is versatile in that it can beadapted to become an extendible backwater valve or can be used to pressure test the lateral or

isolate the lateral if need be. The body of the Mainline Adapt-a-Valve Inspection Chamber has a

special slot molded right into it that is designed to accept the backwater valve gate or the

test/isolation gate. It is the only inspection chamber on the market that can be used as an

inspection chamber, backwater valve and test/isolation device and that is why we call it the

Mainline Adapt-a-Valve Inspection Chamber !



Available in PVC.

The Mainline Adapt-a-Valve Inspection Chamber is constructed to SDR 26 heavy wall sewer

specifications which gives it far more strength and stability than it’s competition. The inspection

chamber is designed for 4” laterals and has an 8” riser. Our improved gasket system features

heavier retained ‘sonic welded’ gaskets that allow easy insertion. The proven Adapt-a-Valve

cassettes and receiver system is now integrated into the inspection chamber as well. This means

that the inspection chamber can be adapted to a backwater valve with the insertion of the

normally open or closed backwater valve gate/cassette or the Test Eze gate can be inserted to

either pressure test the lateral or isolate the lateral. These optional accessories give the fitting the

versatility that no other fitting has! Each body has a directional arrow embossed inside the fitting

that can be used for color coding, to ensure there are no cross connections between sewer andsanitary laterals. The inspection chamber also has a ‘stabilization’ sleeve on the bottom of the

body that allows the use of a 1/2” pipe or re-bar to aid in the stabilizing of the chamber during

the backfill process.

2.7.1 Types of Chambers (h)

2.7.1.1 Access chambers (sh)

These are intended to provide simple access for cursory inspection and access for drain rods or

other maintenance equipment. They are not intended to provide access for a maintenanceoperative and are generally not more than 600mm deep.



Access Chamber - 225-300mm dia

2.7.1.2 Inspection chambers (sh)

(often abbreviated to IC) are larger than access chambers, typically a minimum 450mm diameter.

Again, they provide access for maintenance equipment, but tend to have more branches/spurs

feeding into them and are often up to 1000mm deep.

ICs can be circular, usually 450 or 600mm diameter...



....or they can be rectangular, usually with a concrete cover

2.7.1.3 Manholes (MH) (sh)

are the largest chambers providing access to a sewer or drain for maintenance equipment, and, in

some cases, for operatives to enter the system itself. The minimum internal dimensions of a

manhole are 600x900mm and they can be of any depth, although most modern manholes tend to

be at least 1 metre deep with inspection chambers used for shallower depths.

Manholes tend to have iron covers 600x600mm



2.7.2 Connecting to an existing IC (h)

Most properties built since the 1980's will have circular inspection chambers at key points along

the drainage system, such as changes in direction or junction. By removing the cover and checking

the internal layout of these ICs, it is a simple task to ascertain whether there are 'spare' inletsavailable which can be utilised to form the required new connection. Any 'spare' inlets are usually

stoppered from the outside with a plastic cap to prevent mud or debris from entering the chamber

from the outside.

Any additional new drainage can be connected to the system via one of these inlets provided that

the inlet is the same size or larger than the pipework to be connected. Excavating outside the

chamber will expose the stopper cap, which is then removed and the new pipework connected in

its place. In cases where the inlet is a larger diameter than the pipework being connected, the use of

a taper pipe will allow the connection to be made.

Typical plastic Inspection Chamber

2.7.3 Reflex Connection (h)

One question which has been asked several times concerns connecting a new drainage point to



an existing IC where the direction of flow from the new is opposite to that of the existing. There

seems to be some sort of perception that connecting two pipelines that are effectively running in

opposite directions will cause all sorts of problems.

If the new line was brought in to the IC at 180° to the main direction of flow, this could, incertain arrangements, lead to problems, but what happens in practice is that we construct what

we refer to as a Reflex Connection.

In essence, the line of approach of the new drainage is curved so that it comes into the chamber

at an angle of 90° or less. As usual, this is explained most easily using diagrams...

The scenario is that a linear channel has been installed but the most direct route from the outfallof the end channel to the nearest IC runs counter to the direction of flow in the existing line of

pipes.

The solution is to introduce a bend or curve into the line of pipes connecting the linear

channel to the IC so that the new pipe enters the IC at an angle of 90° or less. By adding a



curve to the line, we are reducing a reflex angle (an angle greater than 90°) to an acute angle

(90° or less) and so 'easing' the inflow of collected water into the main channel and the pre-

existing direction of flow.

The key feature is that the curve, created by using bends, MUST be located immediatelyadjacent to the IC.

In theory, there would be no great problem in setting the bends some distance from the IC. A

rocker pipe of, say, 1m length could be connected to the IC and run out to the right before the

bends necessary to create the required angle of turn are fitted, followed by a straight line of pipes

direct to the linear channel outlet. However, this is not done in practice because once the whole

lot is backfilled and long-forgotten, some future investigation of the drainage system would

assume (quite reasonably) that the pipe line connecting the linear channel to the IC would take

the most direct route and that by digging at a point 1.2m or so to the right of the IC there would

be no chance of accidentally hitting a pipe.

A reflex connection from the rainwater downpipe

2.7.4 Installing a new Inspection Chamber (h)

These polypropylene (PP) Inspection Chambers have a diameter of 450-550mm and cost

around £80. Raising pieces are used to deal with deeper drains, up to a maximum of 1 metre;

anything deeper than 1000mm requires a brick-built or concrete section manhole.

The 100mm types have 5 inlets and one outlet; unused inlets are stoppered to prevent ingress



of spoil. The base unit should be laid on a 100mm thick bed of concrete and the raising

pieces checked for plumb (verticality) before backfilling. If placed within a driveway or

other trafficked area, they should be surrounded with 150mm of concrete all around to

prevent deformation, and a heavy duty cover used. The chamber, or raising pieces, can easily

be cut with a saw to accommodate the frame for the cover at the correct level.

Plastic inspection chamber showing base, raising pieces and cover with frame

The base unit should be connected to the drainage system by means of rocker pipes, that is,

short lengths of pipe, 300-600mm in length that will allow some slight movement of the IC

and/or the rest of the drainage system without imposing and stresses onto the joints.

Details of how these pre-formed inspection chambers can be inserted into an existing line of

drainage using rocker pipes is given on the Connections page.



Inspection Chamber Base Unit

2.7.5 Connecting to an existing manhole (h)

Although pre-formed plastic manholes (much like larger, stronger versions of the ICs illustrated

above) are now becoming popular in the UK building trade, most existing manholes will be either

brick-built or constructed from pre-cast concrete (PCC) sections. With both of these types, it will

be necessary to break into the manhole to install a new connection.

Brick-built manholes typically have 215mm thick brickwork, which can be difficult to break

through, unless a heavy-duty percussion drill is used. Alternatively, it may be possible to 'stitch-drill' the brickwork to make removal by hammer and chisel considerably easier.

PCC manhole sections are usually only 50-60mm thick, although those built beneath vehicular

trafficked areas should have been haunched with mass concrete at least 150mm thick. It is best to

'stitch-drill' these sections to prevent fracture or spalling of individual sections. Use a 13mm

masonry bit to drill holes to the circumference of a circle with a diameter of (external pipe dia +

25mm) at 25-35mm centres. The concrete can then be broken out with hammer and chisel with no

danger of a catastrophic crack.

Stitch drilling



Idealised cutaway manhole

This idealised manhole is shown to illustrate how the channels and benching appear. Benching is

the name given to the infill concrete between the channels and the brickwork. It is always raised

and shaped to prevent sewage or rats lodging thereon.

Although the manhole depicted is brick-built, the same principles apply to pcc section manholes.

Whenever brickwork is used to construct a manhole, whether it is beneath a vehicular area or just

subjected to foot traffic, it should be double-skinned engineering bricks, 215mm wide.

Manhole in plan view



This is our idealised manhole again, shown in plan view. The direction of flow is towards the

bottom of the page, and a channel junction has been used to collect from the inlet pipe on the

right.

A new connection is to be made on the left hand side of the chamber to collect from the soon to

be installed pipework that will connect to a new gully or similar. A hole needs to be made through

the brickwork to allow the pipe into the chamber.

There are two possible ways of installing the new branch to the manhole, depending on the type

of system. On a surface water system, a 'stepped invert' connection is often permissible, but on

foul or combined systems, a 'flush invert' connection is preferred. Both of these methods are

outlined below.

A typical manhole prior to benching...

...and one that's just neen benched



2.7.6 Drop Shaft or Back Drop Connection (h)

In some instances, there may be a significant level difference between the incoming pipe and the

invert level of the manhole. To accommodate this, and to avoid having to excavate to full depth

for the incoming pipe, a Dropshaft connection may be used.

The incoming pipe is projected through into the chamber, to enable rodding and cctv access, and

then stoppered, as shown. A Tumbling Bay Junction is used to divert the flow downwards,

through the vertically set backdrop pipe(s) and then via the knuckle bend to enter the chamber at

invert level.

2.7.7 Surface water systems - stepped invert (h)

2.7.7.1 Over Benching (sh)

In a surface water chamber, it sometimes acceptable (depending on Local Authority Inspectors) to

project the pipe into the chamber in such a way that the bottom of the pipe rests upon the benching

and the water is allowed to discharge over the benching and into the open channel.



It is essential that the new connection discharges its flow in the same direction as the flow of the

existing pipeline, and not 'against the flow'.

Over-benching connection Over-benching branch channel

2.7.7.2 Stepped Slipper Bend Connection (sh)

Alternatively, the base of the branch channel is allowed to sit on the lip

of the main channel, although the branch channel itself is cut to such an

angle that it does not project into/over the main channel itself.

It may be possible to use a 'slipper' bend to form this type of stepped

invert connection.

Stepped Invert Connection SteppedInvert Connection



New pipe brought into an existing MH as an over-bench connection which is yet to bebenched. The pipe entering from the left is a slipper bend stepped invert

Once the branch channel or slipper bend has been positioned on top of the existing benching it

should be secured in place with a granolithic or waterproof mortar, smoothed and shaped to

eliminate any potential snags and sloped to avoid the formation of ledges. The pipe can then be

fixed in place and the hole sealed with the same mortar or a concrete.

Note the maximum measurement (150mm) given for the length of pipe outside the manhole. This is

known as a 'rocker' joint, and is intended to provide flexibility to accommodate any ground

movement. As the manhole chamber is essentially a solid mass held together by concrete, the rocker

joint ensures that small ground movements will not result in pipes being fractured or split. This

applies to both plasticware and clayware.

2.7.7.3 Foul/Combined systems - flush invert (sh)

For a manhole on a Foul system, or a combined system, the above method is not recommended,

primarily because it creates nooks and crannies where sewage may cling, and could, in some

scenarios, cause a blockage to the chamber.

It should also be noted that the warnings given regarding surface water manholes are even more

pertinent to foul systems, and it is strongly recommended that this work is done by competent and



properly trained tradesmen.

To connect to such a manhole, the bottom of the incoming pipe, known as the 'invert level or IL',

must be as close as practicable to the invert level of the existing channel. This can only be achieved

by either breaking out the existing benching on the left-hand side of the idealised manhole to allow anew 'branch channel', sometimes called a 'slipper bend', to link the existing channel with the new

pipe, or by breaking out a section of main channel and the benching to the left hand side and fitting

an appropriate branch junction.

Flush invert - new branch junction

Flush Invert connection

via new branch junction

In this scenario, the new pipework is bedded down on a strong mortar (1:3) within the cut-out

benching which then needs to be re-built. A granolithic mortar is normally used for this purpose, but

any depth of re-building greater than 30mm should be first built up with a semi-dry strong concrete

(1:2:4 or C20) and topped with a 30mm granolithic screed. The finished benching should besmoothed with a steel trowel and should have a fall of not less than 1:30 towards the channels. It is

essential to ensure that there are no 'gaps' that would allow water to penetrate beneath the benching.

There should be no 'snags' or lips on the benching that may impede the free flow of sewage.

2.7.7.4 Constructing a new manhole (sh)

Access and inspection chambers are used when the depth to the drain is a metre or less; for

anything deeper, something more robust is required. The most common forms of manhole

construction are...

o brick-built

o sectional pre-cast concrete



o sectional plastic

o cast in-situ concrete around a plastic liner

For depths up to 2.7m, the minimum internal dimensions for a rectangular manhole are

1200x750mm, although manholes with more than 3 branches may be even bigger. Anythingdeeper than 2.7m is a major project best left to professional drainage contractors.

Plastic Manhole by Polypipe Civils Ltd.

Circular manholes are commonly used for main sewers; for depths up to 1.5m, they must have a

minimum diameter of 1050mm, and for anything deeper than 1.5m, the diameter has to be

1200mm.

This x-section shows a typical construction for a manhole in a residential setting, such as beneath

a driveway. It depicts the two most common constructions, using, on the left, pcc chamber

sections, and on the right, Engineering brickwork.

The cover detail may be different for a manhole within a trafficked area, or if a recess tray coverfor block paving was to be used.

The step-irons should be built into the brickwork, or mortared into the pre-formed holes in pcc

sections. Note the minimum permissible opening size of any manhole is 600x600mm.



Manhole cross-section

Manhole ring section with in-built steps

Rectangular and circular chamber sections ofvarious sizes



Plan view of typical manhole with a single branch oblique junction, again illustrating two

construction types.

The number of branches entering a manhole will determine the length dimension. A manhole

with more than 4 branches may need to be longer to fit them all in. Similarly, manholesutilising 150mm diameter channels may need to be larger.

Full details of manhole dimensions are given in BS8301:1985 Code of Practice for Building

Drainage

If in doubt, consult Local Building Control Office.

Manhole in plan view

Sectional concrete inspection chamber with crown unit and cover



2.7.8 Adoptable Manholes (h)

Only properly trained and qualified construction professionals will be involved in the building of

these types of manholes, and the construction requirements are more fully detailed in the invaluable

groundworkers' bible , Sewers for Adoption 6th Edition 2006 published by the Water ResearchCouncil [ISBN: 1898920028] and generally accepted as the definitive guide to sewer work.

There are several different types of manhole described in SfA4, to suit a variety of purposes and

conditions, but an idealised manhole construction is shown here to illustrate the basic concepts and

components. Not all features depicted will be found on all manholes.

Idealised Adoptable Deep Manhole Cross-section

Idealised Adoptable Deep Manhole Plan View



Some definitions:

o Shallow Manhole - a manhole that has a constant diameter or same cross-section

throughout

o

Deep Manhole - a manhole with an access shaft of a smaller diameter or plan size than themain shaft

o Cover and Frame - see table for guidance on strength rating of various covers

o Seating ring - sometimes used in place of regulating brickwork between cover and cover

slab

o Brickwork - only engineering brick should be used, laid to English Bond

o Corbelling - the method of projecting brickwork outwards to reduce an opening or to carry

a load. Each course should not oversail by more than 50mm

o Cover slab - also known as a 'biscuit'. Best thought of as a 'lid' for the main shaft, with a

single access opening, minimum 600x600mm

o

Reducing slab - used to accommodate a change in chamber diameter from a largerdiameter main shaft to a narrower diameter entrance shaft

o Straight back tapers - perform the same function as reducing slabs, ie to accommodate a

change in shaft diameter, but without providing a landing. Also known as 'Cone Sections'

o Landing Slab - used in Deep Manholes, these limit the maximum shaft depth to 6 metres,

and may be thought of as shaft dividers, providing a resting point or 'landing' at convenient

intervals

PCC Manhole components



o Chamber sections - the individual sections used to construct a sectional shaft. Obviously

not present with brick-built shafts

o Soffit - the underside of a cover slab, arch or other structure. Opposite of Invert

o Benching - a smoothed concrete topping, usually a granolithic mortar, sloping at not less

than 1:30 and neatly shaped and finished to the base of a manholeo Invert - the lowest point on the surface of a pipe, channel or culvert

o Rocker Pipe - a short length of pipe, usually less than 1 metre, placed at the inlet/outlet of

a solid structure, such as a manhole or building, to accommodate differential settlement

between the structure and the drainage system

2.7.9 Cover Slabs (h)

Cover slabs are the 'lid' for many manholes, especially the larger ones. They are also known as'Reducing Slabs', because they reduce the opening size or the chamber dimensions, and, on site,

they are affectionately referred to as 'biscuits' because that's the sort of humour that gets us sent to

serve in the trenches.

The basic role of a cover slab is to provide a firm platform to both 'cap' the chamber and to carry

the cover along with any regulating brickwork. They are typically manufactured in a high-

strength, steel-reinforced concrete, and, for manholes, the minimum opening size of 600x600mm

is created within the cover slab during the casting process. Although the vast majority of cover

slabs are supplied fully-cured from specialist manufacturers, custom slabs may be cast on site and

lifted into position once cured, or, in certain cases, cast in-situ atop the chamber itself.

A secondary role for cover slabs is to reduce the apparent size of the chamber, so that, for

example, a circular 1800mm diameter chamber or a rectangular 1200x750mm chamber, can be



fitted with a standard 600x600mm cover at the surface.

These are heavy items, and they are generally fitted with two or more 'lifting eyes', which are steel

loops embedded into the concrete, that should be used to sling the biscuits from a crane or

excavator during lifting and placement.

The cover slab is normally mortar-bedded onto the top of the chamber with the internal face of the

joint tooled smooth. When the surround concrete is placed around the chamber, it is brought up to

be level with the top of the cover slab, as shown opposite. The regulating brickwork can then be

built on top of the cover slab and the cover and frame fitted to suit the required level.



2.8 Ventilation of house drainage (mh)

In modern plumbing, a drain-waste-vent (or DWV) is part of a system that removes sewage and

greywater from a building and regulates air pressure in the waste-system pipes, facilitating flow.

Waste is produced at fixtures such as toilets, sinks and showers, and exits the fixtures through a

trap, a dipped section of pipe that always contains water. All fixtures must contain traps to

prevent sewer gases from leaking into the house. Through traps, all fixtures are connected to

waste lines, which in turn take the waste to a soil stack, or soil vent pipe. At the building drain

system's lowest point, the drain-waste vent is attached, and rises (usually inside a wall) to and

out of the roof. Waste is removed from the building through the building drain and taken to a

sewage line, which leads to a septic system or a public sewer. Cesspits are generally prohibited

in developed areas.

The venting system, or plumbing vents, consists of pipes leading from waste pipes to the

outdoors, usually through the roof. Vents provide a means to release sewer gases outside instead

of inside the house. Vents also admit oxygen to the waste system to allow aerobic sewage

digestion. Vents provide a way to equalize the pressure on both sides of a trap, thereby allowing

the trap to hold water, which is needed to maintain effectiveness of the trap. Every fixture is

required to have an internal or external trap; double trapping is prohibited by plumbing codes

due to its susceptibility to clogging. With exceptions, every plumbing fixture must have an

attached vent. The top of stacks must be vented too, via a stack vent, which is sometimes called

a stink pipe.

DWV systems maintain neutral air pressure in the drains, allowing flow of water and sewagedown drains and through waste pipes by gravity. As such, it is critical that a downward slope be

maintained throughout. In relatively rare situations, a downward slope out of a building to the

sewer cannot be created, and a special collection pit and grinding lift 'sewage ejector' pump are

needed. By contrast, potable water supply systems operate under pressure to distribute water up

through buildings.

2.8.1 Anti siphonage pipes (h)

Building codes often contain specific sections on back siphonage and especially for externalfaucets. Backflow prevention devices such as anti-siphon valves are required in such designs.

The reason is that external faucets may be attached to hoses which may be immersed in an

external body of water, such as a garden pond, swimming pool, aquarium or washing machine.

Should the pressure within the water supply system fall, the external water may be siphoned back

into the drinking water system through the faucet. Another possible contamination point is the

water intake in the toilet tank. An anti-siphon valve is also required here to prevent pressure



drops in the water supply line from siphoning water out of the toilet tank (which may contain

additives such as "toilet blue") and contaminating the water system. Anti-siphon valves function

as a one-direction check valve.

Anti-siphon valves are also used medically. Hydrocephalus, or excess fluid in the brain, may be

treated with a shunt which drains cerebrospinal fluid from the brain. All shunts have a valve to

relieve excess pressure in the brain. The shunt may lead into the abdominal cavity such that the

shunt outlet is significantly lower than the shunt intake when the patient is standing. Thus a

siphon effect may take place and instead of simply relieving excess pressure, the shunt may act

as a siphon, completely draining cerebrospinal fluid from the brain. The valve in the shunt may

be designed to prevent this siphon action so that negative pressure on the drain of the shunt does

not result in excess drainage. Only excess positive pressure from within the brain should result in

drainage.

Note that the anti-siphon valve in medical shunts is preventing excess forward flow of liquid. In

plumbing systems, the anti-siphon valve is preventing backflow.

2.8.1.1 Other anti-siphoning devices (sh)

Along with anti-siphon valves, anti-siphoning devices also exist. The two are unrelated in

application. Siphoning can be used to remove fuel from tanks. With the cost of fuel increasing, it

has been linked in several countries to the rise in fuel theft. Trucks, with their large fuel tanks,

are most vulnerable. The anti-siphon device prevents thieves from inserting a tube into the fuel

tank.

Siphon barometer

A siphon barometer is the term sometimes applied to the simplest of mercury barometers. A

continuous U-shaped tube of the same diameter throughout is sealed on one end and filled with

mercury. When placed into the upright position, mercury will flow away from the sealed end,

forming a partial vacuum, until balanced by atmospheric pressure on the other end. The term

"siphon" is used because the same principle of atmospheric pressure acting on a fluid is applied.

The difference in height of the fluid between the two arms of the U-shaped tube is the same as

the maximum intermediate height of a siphon. When used to measure pressures other than

atmospheric pressure, a siphon barometer is sometimes called a siphon gauge and not to beconfused with a siphon rain gauge. Siphon pressure gauges are rarely used today.

Siphon bottle



A siphon bottle (also called a soda syphon or, archaically, a siphoid ) is a pressurized bottle with

a vent and a valve. Pressure within the bottle drives the liquid up and out a tube. It is a siphon in

the sense that pressure drives the liquid through a tube. A special form was the gasogene.

Siphon bottles

Siphon cup

A siphon cup is the (hanging) reservoir of paint attached to a spray gun. This is to distinguish it

from gravity-fed reservoirs. An archaic use of the term is a cup of oil in which the oil is siphoned

out of the cup via a cotton wick or tube to a surface to be lubricated.

Siphon rain gauge

A siphon rain gauge is a rain gauge that can record rainfall over an extended period. A siphon is

used to automatically empty the gauge. It is often simply called a "siphon gauge" and is not to be

confused with a siphon pressure gauge.

Heron's siphon

Heron's siphon is a siphon that works on positive air pressure and at first glance appears to be a

perpetual motion machine. In a slightly differently configuration, it is also known as Heron's

fountain.

Venturi siphon



A venturi siphon, also known as an eductor, is essentially a venturi which is designed to greatly

speed up the fluid flowing in a pipe such that an inlet port located at the throat of the venturi can

be used to siphon another fluid. See pressure head. The low pressure at the throat of the venturi is

called a siphon when a second fluid is introduced, or an aspirator when the fluid is air.

Siphonic roof drainage

Siphonic roof drainage makes use of the siphoning principle to carry water horizontally from

multiple roof drains to a single downpipe and to increase flow velocity. Air baffles at the roof

drain inlets reduce the injection of air which causes embolisms in siphons. One benefit to this

drainage technique is the reduction in required pipe diameter to drain a given roof surface area,

up to half the size. Another benefit is the elimination of pipe pitch or gradient required for

conventional roof drainage piping.

Siphon spillway

A siphon spillway in a dam uses the siphon effect to increase the flow rate. A normal spillway

flow is pressurized by the height of the reservoir above the spillway whereas a siphon flow rate

is governed by the difference in height of the inlet and outlet.

2.8.2 vent pipes (h)

To prevent the problems of high pressure in a drain system, sewer pipes will usually vent via one

of two mechanisms.

2.8.2.1 Venting to atmosphere (sh)

Most residential buildings' drainage systems in North America are vented directly through the

buildings' roofs. The DWV pipe is typically ABS or PVC DWV-rated plastic pipe equipped with

a flashing to prevent rainwater from entering the buildings. Older homes may use copper, iron,

lead or clay pipes, in rough order of increasing antiquity.

Under many older building codes, a vent stack, a pipe leading to the main roof vent, is required

to be within a five foot radius of the draining fixture (sink, toilet, shower stall, etc.). To allow

only one vent stack, and thus one roof protrusion as permitted by local building code, sub-vents

may be tied together and exit a common vent stack. One additional requirement for a vent stack

connection is when there are very long horizontal drain runs with very little slope to the run.

Adding a vent connection within the run will aid flow and when used with a clean out allows for

better serviceability of the long run.



A blocked vent is a relatively common problem caused by anything from leaves, to dead

animals, to ice dams in very cold weather. Symptoms range from bubbles in the toilet bowl when

it is flushed, to slow drainage, and all the way to siphoned (empty) traps and sewer gases

entering the building. When a fixture trap is venting properly, a "sucking" sound can often be

heard as the fixture empties out.

2.8.2.2 Island fixture vent (sh)

An island vent is an alternate method for venting sinks and lavatories located where a vertical

vent would not be possible, such as in a kitchen island. The vent pipe rises within the island and

turns down before connecting horizontally to a vent stack.

2.8.3 single stack and double stack system (h)

2.8.3.1 single stack (sh)

This system relies on the principle that the air within the discharge pipes, stack and vent provides

adequate ventilation, considering the number and type of fixtures. No trap vents are required.

The main limitations are the number of fixtures and length of discharge pipes. This type of

system is commonly installed in multi-floor buildings where groups of fixtures are in very close

proximity to the vertical stack. Fixtures must be connected to the stack separately or in groups of

similar fixtures.

2.8.3.2 double stack system (sh)

This system differs from the single-stack system whereby the stack can receive a greater

discharge loading due to the addition of a relief vent and cross vents. No trap vents are required.

This system is used in some buildings where there are a greater number of floor levels than

would be acceptable for a single-stack system.

2.9 Types of fixtures and materials (mh)

Fixtures are usually classified according to the machine for which they were designed. The mostcommon two are milling fixtures and drill fixtures.

Milling fixtures

Milling operations tend to involve large, straight cuts that produce lots of chips and involve

varying force. Locating and supporting areas must usually be large and very sturdy in order to



accommodate milling operations; strong clamps are also a requirement. Due to the vibration of

the machine, positive stops are preferred over friction for securing the work piece. For high-

volume automated processes, milling fixtures usually involve hydraulic or pneumatic clamps.

Drilling fixtures

Drilling fixtures cover a wider range of different designs and procedures than milling fixtures.

Though work holding for drills is more often provided by jigs, fixtures are also used for drilling

operations.

Two common elements of drilling fixtures are the hole and bushing. Holes are often designed

into drilling fixtures, to allow space for the drill bit itself to continue through the work piece

without damaging the fixture or drill, or to guide the drill bit to the appropriate point on the work

piece. Bushings are simple bearing sleeves inserted into these holes to protect them and guide

the drill bit.

Because drills tend to apply force in only one direction, support components for drilling fixtures

may be simpler. If the drill is aligned pointing down, the same support components may

compensate for the forces of both the drill and gravity at once. However, though mono

directional, the force applied by drills tends to be concentrated on a very small area. Drilling

fixtures must be designed carefully to prevent the work piece from bending under the force of the

drill.

A common type of fixture, used in materials tensile testing

2.9.1 sinks (h)

sink (also sinker, hand basin and wash basin) is a bowl-shaped plumbing fixture used for

washing hands, for dishwashing or other purposes. Sinks generally have taps (faucets) that

supply hot and cold water and may include a spray feature to be used for faster rinsing. They also

include a drain to remove used water; this drain may itself include a strainer and/or shut-off

device and an overflow-prevention device. Sinks may also have an integrated soap dispenser.



When a sink becomes stopped-up or clogged, a person will often resort to use a chemical drain

cleaner or a plunger, though most professional plumbers will attack the clog with a drain auger

(often called a "plumber's snake").

A typical sink/basin in a bathroom

An old Butler's (Belfast) sink in a kitchen

2.9.1.1 Materials of the sink (sh)

Sinks are made of many different materials. These include:

• Stainless steel

• Enamel over steel or cast iron

• Ceramic

• Marble



• Plastic

• Soapstone

• Concrete

• Terrazzo

• Wood

•

Stone

• Copper

• Glass

• Granite

• Nickel

Stainless steel is commonly used in kitchens and commercial applications because it represents a

good trade-off between cost, usability, durability, and ease of cleaning. Most stainless steel sinks

are made by drawing a sheet of stainless steel over a die. Some very deep sinks are fabricated by

welding. Stainless steel sinks will not be damaged by hot or cold objects and resist damage fromimpacts. One disadvantage of stainless steel is that, being made of thin metal, they tend to be

noisier than most other sink materials, although better sinks apply a heavy coating of vibration-

damping material to the underside of the sink.

Enamel over cast iron is a popular material for kitchen and bathroom sinks. Heavy and durable,

these sinks can also be manufactured in a very wide range of shapes and colors. Like stainless

steel, they are very resistant to hot or cold objects, but they can be damaged by sharp impacts and

once the glass surface is breached, the underlying cast iron will often corrode, spalling off more

of the glass. Aggressive cleaning will dull the surface, leading to more dirt accumulation.

Enamel over steel is a similar-appearing but far less rugged and less cost-effective alternative.

Solid ceramic sinks have many of the same characteristics as enamel over cast iron, but without

the risk of surface damage leading to corrosion.

Plastic sinks come in several basic forms:

• Inexpensive sinks are simply injection-molded thermoplastics. These are often deep, free-

standing sinks used in laundry rooms. Subject to damage by hot or sharp objects, the

principal virtue of these sinks is their low cost.

• High-end acrylic drop-in (lowered into the countertop) and undermount (attached from

the bottom) sinks are becoming more popular, although they tend to be easily damaged

by hard objects - like scouring a cast iron frying pan in the sink.

• Plastic sinks may also be made from the same materials used to form "solid surface"

countertops. These sinks are durable, attractive, and can often be molded with an



integrated countertop or joined to a separate countertop in a seamless fashion, leading to

no sink-to-countertop joint or a very smooth sink-to-countertop joint that can not trap dirt

or germs. These sinks are subject to damage by hot objects but damaged areas can

sometimes be sanded-down to expose undamaged material.

Soapstone sinks were once common, but today tend to be used only in very-high-end

applications or applications that must resist caustic chemicals that would damage more-

conventional sinks.

Wood sinks are from the early days of sinks and baths were made from natural teak with no

additional finishing. Teak is chosen because of its natural waterproofing properties – it has been

used for hundreds of years in the marine industry for this reason. Teak also has natural antiseptic

properties, which is a bonus for its use in baths and sinks.

Glass sinks: A current trend in bathroom design is the handmade glass sink (often referred to as a

vessel sink) which has become fashionable for wealthy homeowners.

Stone sinks have been used for ages. Some of the more popular stones used are: marble,

travertine, onyx, granite, and soap stone on high end sinks.

Glass, concrete, and terrazzo sinks are usually designed for their aesthetic appeal and can be

obtained in a wide variety of unusual shapes and colors such as floral shapes. Concrete and

terrazzo are occasionally also used in very-heavy-duty applications such as janitorial sinks.

2.9.2 baths (h)

From lavatory faucets to bathtub drains, toilets and shower heads to soap dispensers and other

accessories, Delta has every fixture for your bathroom. Browse bath products by product type, or

scroll below to browse by collection, decorating style or new products.

Bathroom faucets (also known as lavatory faucets or sink faucets) are central to even the smallest

bathrooms. That’s why replacing your bath faucet is one of the quickest and easiest ways to

update a bathroom.

2.9.3 water closets (h)

This product category applies to PVRS credit PW-R1: Minimum Interior Water Use Reduction

and can assist for the optional credit PW-1 Improved Interior Water Use Reduction to achieve a

higher Pearl rating. These credits require manufacturer information of all proposed water fixtures

and fittings indicating flow rates at a specified pressures. Following feedback from consultants,



manufacturer data is often not supplied at the specified pressures and researching manufacturer

data can often be time consuming.

PW-R1 Requirements

PW-R1: Minimum Water Use Reduction of the PVRS requires the specification and installationof fixtures and fittings which have the maximum flow rates at specified pressures listed below:

Fixture or Fitting Maximum flowrate or quantity

Bathroom Taps 6.0 litres/min at 413.7 kPa (reference pressure)

Shower Head 9.5 litres/min at 551.6 kPa (reference pressure)

Kitchen Taps 6.0 litres/min at 413.7 kPa (reference pressure)

Bidets 6.0 litres/min at 413.7 kPa (reference pressure)

Toilets (Dual Flush) 6.0/4.0 litres/flushing cycle (full/low)

Submission Process

In order to demonstrate compliance with the credit requirements, project teams can either use the

standard submittal templates with all supporting documentation or the EVPD Submittal

Template : Water Fixtures and Fittings below.

• EVPD Submittal Template : Water Fixtures and Fittings.

This spreadsheet contains a complete schedule that is automatically generated including all

relevant information for inclusion for the PW-R1 submission as follows:

• Manufacturer

• EVPD and Manufacturer Reference Numbers

• Flow Rate at Required Pressure

If you want to use a product that is not on the EVPD, please follow the Conventional Villa

Product Selection Pathway.

Estidama Villa Product Database - Water Fixtures & Fittings

The Estidama Villa Product Database (EVPD)-Water Fixtures provides the following

information:

• Manufacturer name



• EVPD Reference

• Image of product

• Model

• Manufacturer's product reference number

• Summary details

•

Flow rates at required pressures (or flush volumes)

• Sales contact details.

2.9.4 flushing cisterns (h)

In an average home, up to 30% of water use is for toilet flushing. This can be reduced by:

• ensuring a dual flush cistern is specified

• installing a water-efficient toilet pan

•

using collected rainwater or treated greywater for flushing

• installing waterless composting toilets where no mains sewer connection is available.

Many older cisterns use far more water than necessary – typically 12 litres is used. To reduce the

amount of water used, replace the inefficient cistern with a modern dual-flush one. (A new pan

may be needed where a dual flush cistern cannot be fitted to the existing one.)

If fitting a new pan/cistern is impractical, options you can use to reduce water usage include:

• placing an object such as a brick, or plastic milk bottle filled with water that has the top

firmly screwed on into the cistern to reduce the amount of water required to fill an older

cistern

• adjusting the float ball by bending it down slightly to reduce the volume of water in the

cistern – ensure that sufficient flow and volume is maintained for an adequate flush

• ensuring that the cistern supply shuts off fully when not in use.

In all cases, sufficient flow and volume must be maintained so the pan is cleared with a single

flush.

2.9.5 urinals (h)

A urinal (pronounced / j r n əl/) is a specialized toilet for urination only. It can take the form

of a container or simply a wall, with drainage and automatic or manual flushing.

While urinals are generally intended for use by males, it is also possible for females to use them.

The different types of male urinal, for single users or trough designs for multiple users, are



intended to be utilized from a standing position. Designers of urinals for women have adopted

various approaches: some intending the user to "hover" over the unit, facing away from it, others

intending the user to stand facing the urinal, with or without a female urination device. While

uncommon due to restroom segregation, it is possible for females to use male urinals.[1]

Public urinals usually have a plastic mesh guard, which may contain a deodorizing urinal

deodorizer block or "urinal cake". The mesh is intended to prevent solid objects (such as

cigarette butts, feces, chewing gum, or paper) from being flushed and possibly causing a

plumbing stoppage. In some restaurants, bars, and clubs, ice may be put in the urinals, serving

some of the same purposes as the deodorizing block.

The term may also apply to a small building or other structure containing such toilets. It can also

refer to a small container in which urine can be collected for medical purposes, or for use where

access to toilet facilities is not possible, such as in small aircraft or for the bedridden.

Urinal with urinal cake

Marcel Duchamp's Fountain, a urinal which Duchamp signed "R. Mutt" and exhibited as an

artwork



2.9.6 Septic tanks (h)

A septic tank is a key component of the septic system, a small-scale sewage treatment system

common in areas with no connection to main sewage pipes provided by local governments or

private corporations. (Other components, typically mandated and/or restricted by local

governments, optionally include pumps, alarms, sand filters, and clarified liquid effluent disposal

means such as a septic drain field, ponds, natural stone fiber filter plants or peat moss beds.)

Septic systems are a type of On-Site Sewage Facility (OSSF). In North America, approximately

25% of the population relies on septic tanks; this can include suburbs and small towns as well as

rural areas (Indianapolis is an example of a large city where many of the city's neighborhoods are

still on separate septic systems). In Europe, they are in general limited to rural areas only. Since a

septic system requires a drainfield that uses a lot of land area, they are not suitable for densely

built cities.

The term "septic" refers to the anaerobic bacterial environment that develops in the tank which

decomposes or mineralizes the waste discharged into the tank. Septic tanks can be coupled with

other onsite wastewater treatment units such as biofilters or aerobic systems involving artificial

forced aeration.

Periodic preventive maintenance is required to remove the irreducible solids that settle and

gradually fill the tank, reducing its efficiency. In most jurisdictions this maintenance is required

by law, yet often not enforced. According to the Environmental Protection Agency, in the United

States it is the home owner's responsibility to maintain their septic system. Those who disregard

the requirement will eventually be faced with extremely costly repairs when solids escape the

tank and destroy the clarified liquid effluent disposal means. A properly maintained system, onthe other hand, can last for decades or possibly even a lifetime.

A septic tank before installation



2.9.7 Dispersion trench (h)

Runoff dispersed by these trenches is diffused and reduced in velocity, thereby reducing

incidences of onsite erosion and adverse effects of runoff reaching downstream locations.

Some infiltration is promoted as well as storage.

The same tank partially installed in the ground

Septic tank scheme



2.9.8 soak pits (h)

A Soak Pit, also known as a soakaway or leach pit, is a covered, porous-walled chamber that

allows water to slowly soak into the ground. Pre-settled effluent from a Collection and

Storage/Treatment or (Semi-) Centralized Treatment technology is discharged to the

underground chamber from where it infiltrates into the surrounding soil.

The Soak Pit can be left empty and lined with a porous material (to provide support and prevent

collapse), or left unlined and filled with coarse rocks and gravel. The rocks and gravel will

prevent the walls from collapsing, but will still provide adequate space for the wastewater. In

both cases, a layer of sand and fine gravel should be spread across the bottom to help disperse

the flow. The soak pit should be between 1.5 and 4m deep, but never less than 1.5m above the

ground water table.

As wastewater (pre-treated greywater or blackwater) percolates through the soil from the Soak

Pit, small particles are filtered out by the soil matrix and organics are digested by micro-

organisms. Thus, Soak Pits are best suited to soils with good absorptive properties; clay, hard

packed or rocky soils are not appropriate.

Advantages Disadvantages/limitations

- Can be built and repaired with locally

available materials.

- Small land area required.

- Low capital cost; low operating cost.

- Can be built and maintained with locally

available materials.

- Simple technique for all users.

- Pretreatment is required to prevent clogging,

although eventual clogging is inevitable.

- May negatively affect soil and groundwater

properties.

Adequacy

A Soak Pit does not provide adequate treatment for raw wastewater and the pit will clog quickly.

A Soak Pit should be used for discharging presettled blackwater or greywater. Soak pits are

appropriate for rural and peri-urban settlements. They depend on soil with a sufficient absorptive

capacity. They are not appropriate for areas that are prone to flooding or have high groundwatertables.

Health Aspects/Acceptance

As long as the Soak Pit is not used for raw sewage, and as long as the previous Collection and

Storage/Treatment technology is functioning well, health concerns are minimal. The technology



is located underground and thus, humans and animals should have no contact with the effluent. It

is important however, that the Soak Pit is located a safe distance from a drinking water source

(ideally 30m). Since the Soak Pit is odourless and not visible, it should be accepted by even the

most sensitive communities.

Maintenance

A well-sized Soak Pit should last between 3 and 5 years without maintenance. To extend the life

of a Soak Pit, care should be taken to ensure that the effluent has been clarified and/or filtered

well to prevent excessive build up of solids. The Soak Pit should be kept away from high-traffic

areas so that the soil above and around it is not compacted. When the performance of the Soak

Pit deteriorates, the material inside the soak pit can be excavated and refilled. To allow for future

access, a removable (preferably concrete) lid should be used to seal the pit until it needs to be

maintained. Particles and biomass will eventually clog the pit and it will need to be cleaned or

moved.

Review Questions

1. Explain Principles of drainage.

2. Define surface drainage combined and separate system of drainage.

3. Explain shape and sizes of drains and sewers.

4. What are storm water over flow chambers?

5.

Describe methods of laying and construction of sewers.6. Explain House drainage: traps – shapes, sizes, types, materials and function.

7. Describe Surface water systems - stepped invert.

8. Define Ventilation of house drainage.

9. Describe types of fixtures and materials.



Chaper-3

SOLID WASTE DISPOSAL (ch)

Structure of this unitSolid Wastes

Learning Objectives1. Properties of Solid Wastes

2. Management of Solid Wastes in India

3. Disposal of Wastes

3.1 Properties of Solid Wastes (mh)

1. Source Information for the Individual Points of Origin

• Waste components, individually or at least by classes

• Rate of discharge during production run (average and maximum)

• Periodic discharges due to batch operations.

• Duration and frequency of production runs

• Susceptibility to emergency discharges or spills

2. Chemical Composition

• Organic and inorganic components by compounds or classes

•

Gross organic: Chemical oxygen demand (COD), total organic carbon (TOD),

biochemical oxygen demand (BOD, extractable

• Specific problem ions (As, Ba, Cd, Cr, CN, Hg, Pb, Sc, Ag, NO3

• Specific problem organic, e.g. phenol, certain pesticides, benzidine,

• polychlorinated biphenyls, certain polynuclear aromatics

• Total dissolved salts

• pH, acidity, alkalinity

• Nitrogen and phosphorus



• Oils and greases (extractables)

• Oxidizing or reducing agents (e.g, sulfides)

• Surfactants

•

Chlorine demand

3. Biological Effects

• Biochemical oxygen demand

• Toxicity (acquatic life, bacteria, mammals, plants)

• Pathogenic bacteria

4. Physical Properties

• Temperature range and distribution

• Insoluble components: Colloidal, settleable, floatable

• Colour

• Odour

• Foamability

•

Corrosiveness

• Radioactivity

5. Flow Data for Total Discharge

• Average daily flow rate

• Duration and level of minimum flow rate

• Maximum rate of change of flow rate

3.1.1 Physical and chemical composition of municipal solid wastes (h)

3.1.1.1 Physical Composition (sh)

Information and data on the physical composition of solid wastes are important in the selection

and operation equipment and facilities, in assessing the feasibility and resources and energy



recovery and in the analysis and design of disposal facilities. Waste composition, moisture

content, waste particle size, waste density, temperature and pH are important as these affect the

extent and rate of degradation of waste. These are determined on components of solid wastes.

Determination of Characteristics in the Field

Solid wastes are complex, multiphase mixtures. Because of the heterogeneous nature of solid

wastes, determination of composition is not easy. Statistical procedures are difficult and usually

procedures based on random sampling techniques are used to determine composition.

To obtain a sample for analysis the waste is reduced to about 100 kg by coning and quartering.

Moisture Content:

The moisture content of solid wastes usually is expressed as the weight of moisture per unit

weight of wet or dry material. In the wet-weight method of measurement, the moisture in a

sample is expressed as a percentage of the wet weight of the material; in the dry-weight method,it is expressed as a percentage of the dry weight of the material. In equation form, the wet-

weight moisture content is expressed as follows:

Moisture content (%) =a b

a

−⎛

⎝ ⎜

⎠⎟1 0 0

where a = initial weight of sample as delivered

b = weight of sample after drying

Typical data on the moisture content for the solid waste components are given in Table2(Tchobanoglous et al. (1977). For most municipal solid wastes, the moisture content will vary

from 15 to 40 percent, depending on the composition of the wastes, the season of the year, and

the humidity and weather conditions, particularly rain. Most micro-organisms including bacteria

require a minimum of approximately 12% moisture for growth. It was shown that the log of the

rate of gas production is directly proportional to the percentage of water content of refuse (Rees,

1980).

Density:

Density data are often needed to assess the total mass and volume of water that must bemanaged. Unfortunately, there is little or no uniformity in the way solid waste densities have

been reported in the literature. Often, no distinction has been made between uncompacted or

compacted densities. Typical densities for various wastes as found in containers are reported by

source in Table .

Because the densities of solid wastes vary markedly with geographic location, season of the year,

the length of time in storage, great care should be used in selecting typical values. Municipal



solid wastes as delivered in compaction vehicles have been found to have a typical value about

300 kg/m3.

Particle Size and size distribution:

The size and size distribution of the component materials in solid wastes are an importantconsideration in the recovery of materials, especially with mechanical means such as trommel

screens and magnetic separators. The size of a waste component may be defined by one or more

of the following measures:

Where Sc = size of component, in (mm)

L = length, in (mm)

W = width, in (mm)

H= height, in (mm)

The major means of controlling particle size is through shredding. Shredding increases

homogeneity, increases the surface area/volume ratio and reduces the potential for preferential

liquid flow paths through the waste.

Particle size will also influence waste packing densities, and particle size reduction (by

shredding) could increase biogas production through the increased surface area available to

degradation by bacteria. But the smaller particles allow higher packing density which decrease

water movement, bacterial movement and the bacterial access to substrate.

Field Capacity

lS c =

⎟ ⎠

⎞⎜⎝

⎛ +=

2

wlS c

⎟ ⎠

⎞⎜⎝

⎛ ++=

3

hwlS c

( )2

1

wlS c ×=

( )3

1

hwlS c ××=



The ultimate analysis of a waste component typically involves the determination of the percent C

(carbon), H (hydrogen), O (oxygen), N (nitrogen), S (sulphur), and ash. Because of the concern

over the emission of chlorinated compounds during combustion, the determination of halogens is

often included in an ultimate analysis. The results of the ultimate analysis are used to

characterise the chemical composition of the organic matter in MSW. They are also used to

define the proper mix of waste materials to achieve suitable C/N ratios for biological conversion

processes.

Energy Content of Solid Waste Components

The energy content of the organic components in MSW can be determined

(1) by using a full scale boiler as a calorimeter,

(2) by using a laboratory bomb calorimeter, and

(3) by calculation, if the elemental composition is known.

Because of the difficulty in instrumenting a full-scale boiler, most of the data on the energy

content of the organic components of MSW are based on the results of bomb calorimeter tests.

Essential Nutrients and Other Elements

Where the organic fraction of MSW is to be used as feedstock for the production of biological

conversion products such as compost, methane, and ethanol, information on the essential

nutrients and elements in the waste materials is of importance with respect the microbial nutrent balance and in assessing what final uses can be made of the materials remaining after biological

conversion.

Representative data on the ultimate analysis of typical municipal waste components are

presented in Table 5. If Btu values are not available, the approximate Btu value can be

determined by using Eq. .

Btu/lb = 145.5C + 620(H -1

8O) = 41S

where C = carbon, percent

H = hydrogen, percent

O = oxygen, percent

S = sulphur, percent



Chemical compositions of Municipal Solid waste dumps of three cities are summarised in Table.

Future Changes in Composition

In terms of solid waste management planning, knowledge of future trends in the composition of

solid wastes is of great importance. For example, if a paper recycling program were instituted onthe basis of current distribution data and if paper production were to be eliminated in the future,

such a program would more than likely become a costly “white elephant”. Although this case is

extreme, it nevertheless illustrates the point that future trends must be assessed carefully in long-

term planning. Another important question is whether the quantities are actually changing or

only the reporting system has improved.

Treatment methods:

Suitability of various treatment methods depends on physical and chemical characteristics of

waste. The method of treatment is decided based on moisture content, organic matter and total

solids.

3.1.2 waste generation rates (h)

Waste generation varies as a function of affluence, however, regional and country variations can

be significant, as can generation rates within the same city. Annex A. Map of Regions illustrates

the regional classification used in this report. Throughout the report, when Africa is mentioned

as a region, we refer to Sub-Saharan Africa. Data are particularly lacking for Sub-Saharan

Africa. Waste generation in sub-Saharan Africa is approximately 62 million tonnes per year. Per

capita waste generation is generally low in this region, but spans a wide range, from 0.09 to 3.0

kg per person per day, with an average of 0.65 kg/capita/day. The countries with the highest per

capita rates are islands, likely due to waste generated by the tourism industry, and a more

complete accounting of all wastes generated. The annual waste generation in East Asia and the

Pacific Region is approximately 270 million tonnes per year. This quantity is mainly influenced

by waste generation in China, which makes up 70% of the regional total. Per capita waste

generation ranges from 0.44 to 4.3 kg per person per day for



the region, with an average of 0.95 kg/capita/day. In Eastern and Central Asia, the waste

generated per year is at least 93 million tonnes. Eight countries in this region have no available

data on waste generation in the literature. The per capita waste generation ranges from 0.29 to

2.1 kg per person per day, with an average of 1.1 kg/capita/day. Latin America and the

Caribbean has the most comprehensive and consistent data (e.g. PAHO’s Regional Evaluation of

Solid Waste Management, 2005). The total amount of waste generated per year in this region is

160 million tonnes, with per capita values ranging from 0.1 to 14 kg/capita/ day, and an average

of 1.1 kg/capita/day. Similar to the high per capita waste generation rates on islands in Africa,

the largest per capita solid waste generation rates are found in the islands of the Caribbean. In the

Middle East and North Africa, solid waste generation is 63 million tonnes per year. Per capitawaste generation is 0.16 to 5.7 kg per person per day, and has an average of 1.1 kg/capita/day.

The OECD countries generate 572 million tonnes of solid waste per year. The per capita values

range from 1.1 to 3.7 kg per person per day with an average of 2.2 kg/capita/day.



3.2 Management of Solid Wastes in India (mh)

Solid waste policy in India specifies the duties and responsibilities for hygienic waste

management for cities and citizens of India. This policy was framed in September 2000, based

on the March 1999 Report of the Committee for Solid Waste Management in Class 1 Cities of

India to the Supreme Court, which urged statutory bodies to comply with the report’s

suggestions and recommendations. These also serve as a guide on how to comply with the MSW

rules. Both the report and the rules, summarized below, are based on the principle that the best

way to keep streets clean is not to dirty them in the first place. So a city without street bins will

ultimately become clean and stay clean. They advocate daily doorstep collection of “wet” (food)

wastes for composting, which is the best option for India. This is not only because composting is

a cost-effective process practiced since Vedic times, but also because India’s soils need organic

manures to prevent loss of fertility through unbalanced use of chemical fertilizers.

Municipality Solid Waste Rules To stop the present unplanned open dumping of waste outside

city limits, the MSW rules have laid down a strict timetable for compliance: improvement of

existing landfill sites by end-2001, identification of landfill sites for long-term future use and

making them ready for operation by end-2002, setting up of waste-processing and disposal

facilities by end-2003, and provision of a buffer zone around such sites. Biodegradable wastes

should be processed by composting, vermicomposting etc. and landfilling shall be restricted to

non-biodegradable inert waste and compost rejects.

The rules also require municipalities to ensure community participation in waste segregation (bynot mixing “wet” food wastes with “dry” recyclables like paper, plastics, glass, metal etc.) and to

promote recycling or reuse of segregated materials. Garbage and dry leaves are not allowed to be

burnt. Biomedical wastes and industrial wastes are not allowed to be mixed with municipal

wastes. Routine use of pesticides on garbage has been banned by the Supreme Court on

28.7.1997.

Littering and throwing of garbage on roads is prohibited. Citizens should keep their wet (food)

wastes and dry (recyclable) wastes within their premises until collected, and must ensure

delivery of wastes as per the collection and segregation system of their city, preferably by house-

to-house collection at fixed times in multi-container handcarts or tricycles (to avoid manualhandling of waste) or directly into trucks stopping at street corners at regular pre-informed

timings. Dry wastes should be left for collection by the informal sector (sold directly to waste-

buyers or given free or otherwise to waste-pickers, who will earn their livelihood by taking the

wastes they need from homes rather than from garbage on the streets. High - rises, private

colonies, institutions should provide their own big bins within their own areas, separately for dry

and wet wastes.



Report of a Committee for Solid Waste Management in Class 1 Cities of India to theSupreme Court The report recommends that cities should provide free waste collection for all

slums and public areas, but charge the full cost of collection on “Polluter-Pays” Principle, from

hotels, eateries, marriage halls, hospitals & clinics, wholesale markets, shops in commercial

streets, office complexes, cattle - sheds, slaughter - houses, fairs & exhibitions, inner-city cottage

industry & petty trade. Debris and construction waste must be stored within premises, not on the

road or footpath, and disposed of at pre - designated sites or landfills by builder, on payment of

full transport cost if removed by the Municipality.

For improved work accountability, “pin-point” work assignments and 365-day cleaning are

recommended, with fixed beats for individual sweepers, including the cleaning of adjoining

drains less than 2 ft deep. Drain silt should not be left on the road for drying, but loaded directly

into hand-carts and taken to a transfer point . Silt and debris should not be dumped at compost -

plant.

The quantities of garbage collected and transported need to be monitored against targets,

preferably by citizen monitoring, through effective management information systems and a

recording weigh - bridge: computerised for 1 million+ cities. At least 80% of waste-clearance

vehicles should be on-road, and two-shift use implemented where there is a shortage of vehicles.

Decentralised ward-wise composting of well-segregated wet waste in local parks is

recommended, for recycling of organics and also for huge savings in garbage transport costs to

scarce disposal sites.

The report also recommends that waste-management infrastructure should be a strictly-enforced

pre-condition in new development areas. It advocates temporary toilets at all construction sites(located on the eventual sewage-disposal line) and restriction of cattle movement on streets.

Livestock should be stall-fed or relocated outside large cities.

Cities must fulfil their obligatory functions (like waste management) before funding any

discretionary functions, while being granted fiscal autonomy to raise adequate funds. Solid-

waste-management and other charges should be linked to the cost-of-living index, along with

levy of “administrative charges” for chronic littering. Funds should be earmarked for minimum

expenditure on solid waste management: Rs 100 per capita per year in 5-lakh-plus cities, or a

minimum of Rs 50 per capita in smaller towns. Many cities are already providing conditional

funding to residential areas or colonies willing to take responsibility for improved waste-management of their respective areas.

The Supreme Court intends to monitor compliance with the MSW rules through the High Courts

in each State. This gives all citizens both the opportunity and the obligation to ensure that

hygienic waste-management becomes a reality, soon.



3.2.1 Prevalent SWM practices and deficiencies (h)

3.2.1.1 Storage of waste at source (sh)

Storage of waste at source is the first essential step of Solid Waste Management. Every

household, shop and establishment generates solid waste on day to day basis. The waste should

normally be stored at the source of waste generation till collected for its disposal. In India, such a

habit has not been formed and in the absence of system of storage of waste at source, the waste is

thrown on the streets, treating streets as receptacle of waste. If citizens show such apathy and

keep on throwing waste on streets and expect that municipal sweepers should/would clean the

city, the cities will never remain clean. Even if local bodies make arrangements to remove all the

waste disposed of by the citizens on the street on day to day basis, the city will remain clean only

for two to three hours and not beyond till the habit of throwing waste on the streets is not

changed. There is, therefore, a need to educate the people to store waste at source, dispose of thewaste as per the directions of the local bodies and effectively participate in the activities of the

local bodies to keep the cities clean.

3.3 Disposal of Wastes (mh)

Waste management is the collection, transport, processing or disposal, managing and

monitoring of waste materials. The term usually relates to materials produced by human activity,

and the process is generally undertaken to reduce their effect on health, the environment or

aesthetics. Waste management is a distinct practice from resource recovery which focuses ondelaying the rate of consumption of natural resources. All waste materials, whether they are

solid, liquid, gaseous or radioactive fall within the remit of waste management.

Waste management practices can differ for developed and developing nations, for urban and

rural areas, and for residential and industrial producers. Management of non-hazardous waste

residential and institutional waste in metropolitan areas is usually the responsibility of local

government authorities, while management for non-hazardous commercial and industrial waste

is usually the responsibility of the generator subject to local, national or international authorities.

3.3.1 Sanitary landfilling (h)

Disposal of waste in a landfill involves burying the waste, and this remains a common practice in

most countries. Landfills were often established in abandoned or unused quarries, mining voids

or borrow pits. A properly designed and well-managed landfill can be a hygienic and relatively

inexpensive method of disposing of waste materials. Older, poorly designed or poorly managed



landfills can create a number of adverse environmental impacts such as wind-blown litter,

attraction of vermin, and generation of liquid leachate. Another common product of landfills is

gas (mostly composed of methane and carbon dioxide), which is produced as organic waste

breaks down anaerobically. This gas can create odor problems, kill surface vegetation, and is a

greenhouse gas.

Design characteristics of a modern landfill include methods to contain leachate such as clay or

plastic lining material. Deposited waste is normally compacted to increase its density and

stability, and covered to prevent attracting vermin (such as mice or rats). Many landfills also

have landfill gas extraction systems installed to extract the landfill gas. Gas is pumped out of the

landfill using perforated pipes and flared off or burnt in a gas engine to generate electricity.

A landfill compaction vehicle in action.

3.3.2 Composting (h)

Compost is organic matter that has been decomposed and recycled as a fertilizer and soil

amendment. Compost is a key ingredient in organic farming. At the simplest level, the process of

composting simply requires making a heap of wetted organic matter (leaves, "green" food waste)

and waiting for the materials to break down into humus after a period of weeks or months.

Modern, methodical composting is a multi-step, closely monitored process with measured inputs

of water, air, and carbon- and nitrogen-rich materials. The decomposition process is aided by

shredding the plant matter, adding water and ensuring proper aeration by regularly turning the

mixture. Worms and fungi further break up the material. Aerobic bacteria manage the chemical

process by converting the inputs into heat, carbon dioxide and ammonium. The ammonium is

further converted by bacteria into plant-nourishing nitrites and nitrates through the process of

nitrification.

Compost can be rich in nutrients. It is used in gardens, landscaping, horticulture, and agriculture.

The compost itself is beneficial for the land in many ways, including as a soil conditioner, a

fertilizer, addition of vital humus or humic acids, and as a natural pesticide for soil. In

ecosystems, compost is useful for erosion control, land and stream reclamation, wetland



construction, and as landfill cover (see compost uses). Organic ingredients intended for

composting can alternatively be used to generate biogas through anaerobic digestion. Anaerobic

digestion is fast overtaking composting in some parts of the world (especially central Europe) as

a primary means of downcycling waste organic matter.

3.3.2.1 Composting approaches (sh)

In addition to the traditional compost pile, various approaches have been developed to handle

different composting processes, ingredients, locations, and applications for the composted

product.

Grub composting

Grub composting uses the black soldier fly larvae (BSFL) to quickly convert manure or kitchen

waste into an animal feed for poultry, fish, pigs, lizards, turtles, and possibly dogs. In a grub bin,

BSFL self-harvest when mature by crawling into a separate collection container. The harvested

grubs are exceptionally nutritious and medicinal for poultry. This is probably the fastest

composting technique. The composted residue can be used as a soil amendment or as food for

worms (redworms).

BSFL often appear naturally in worm bins, composting toilets, or compost bins. Without much

added cost, these devices could be designed to also harvest BSFL.

Bokashi

Inside a recently started bokashi bin. The aerated base is just visible through the food scraps and

bokashi bran.

Bokashi is a method that uses a mix of microorganisms to cover food waste to decrease smell. It

derives from the practice of Japanese farmers centuries ago of covering food waste with rich,

local soil that contained the microorganisms that would ferment the waste. After a few weeks,

they would bury the waste that weeks later, would become soil.



Most practitioners obtain the microorganisms from the product Effective Microorganisms

(EM1), first sold in the 1980s. EM1 is mixed with a carbon base (e.g. sawdust or bran) that it

sticks to and a sugar for food (e.g. molasses). The mixture is layered with waste in a sealed

container and after a few weeks, removed and buried. EM primarily composted of lactica acid

bacteria, yeast and phototrophic (PNSB) bacteria.

Newspaper fermented in a lactobacillus culture can be substituted for bokashi bran for a

successful bokashi bucket.

Compost tea

Compost tea is a liquid extract or a dissolved solution but not simply a suspension of compost. It

is made by steeping compost in water for 3–7 days. It was discovered in Germany and became a

practice to suppress foliar fungal diseases by nature of the bacterial competition, suppression,

antibiosis on the leaf surface (phyllosphere). It has also been used as a fertilizer although lab

tests show it is very weak in nutrients with less than 100ppm of available nitrogen and

potassium. Other salts present in the tea solution are sodium, chlorides and sulfates. The extract

is applied as a spray to non-edible plant parts such as seedlings, or as a soil-drench (root dip), or

as a surface spray to reduce incidence of harmful phytopathogenic fungi in the phyllosphere.

Hügelkultur

The practice of making raised garden beds filled with rotting wood. It is in effect creating a

Nurse log, however, covered with dirt.

Benefits of hügelkultur garden beds include water retention and warming of soil. Buried wood

becomes like a sponge as it decomposes, able to capture water and store it for later use by crops

planted on top of the hugelkultur bed.

The buried decomposing wood will also give off heat, as all compost does, for several years.

These effects have been used by Sepp Holzer for one to allow fruit trees to survive at otherwise

inhospitable temperatures and altitudes.

"Humanure"

"Humanure" is a portmanteau neologism designating human excrement (feces and urine) that is

recycled via composting for agricultural or other purposes. The term was first used in a 1994

book by Joseph Jenkins that advocates the use of this organic soil amendment.

Humanure is not sewage that has been processed by waste-treatment facilities, which may

include waste from industrial and other sources; rather, it is the combination of feces and urine

with paper and additional carbon material (such as sawdust). A humanure system, such as a



compost toilet, does not require water or electricity, and when properly managed does not smell.

A compost toilet collects human excrement which is then added to a hot compost heap together

with sawdust and straw or other carbon rich materials, where pathogens are destroyed. A

composting toilet processes the waste in situ. Because the term "humanure" has no authoritative

definition it is subject to misuse; news reporters occasionally fail to correctly distinguish

between humanure and "sewer sludge" or "biosolids".

By disposing of feces and urine through composting, the nutrients contained in them are returned

to the soil. This aids in preventing soil degradation. Human fecal matter and urine have high

percentages of nitrogen, phosphorus, potassium, carbon, and calcium. It is equal to many

fertilizers and manures purchased in garden stores. Humanure aids in the conservation of fresh

water by avoiding the usage of potable water required by the typical flush toilet. It further

prevents the pollution of ground water by controlling the fecal matter decomposition before

entering the system. When properly managed, there should be no ground contamination from

leachate.

As a substitute for a flush water process, it reduces the energy consumption and, hence,

greenhouse gas emissions associated with the transportation and processing of water and waste

water.

Humanure may be deemed safe for humans to use on crops if handled in accordance with local

health regulations, and composted properly. This means that thermophilic decomposition of the

humanure must heat it sufficiently to destroy harmful pathogens, or enough time must have

elapsed since fresh material was added that biological activity has killed any pathogens. To be

safe for crops, a curing stage is often needed to allow a second mesophilic phase to reduce potential phytotoxins.

Humanure is different from night soil, which is raw human waste spread on crops. While aiding

the return of nutrients in fecal matter to the soil, it can carry and spread a number of human

pathogens. Humanure kills these pathogens both by the extreme heat of the composting and the

extended amount of time (1 to 2 years) that it is allowed to decompose. Complete pathogen

destruction is guaranteed by arriving at a temperature of 62 °C (144 °F) for one hour, 50 °C

(122 °F) for one day, 46 °C (115 °F) for one week or 43 °C (109 °F) for one month.

Vermi compost



Rotary screen harvested worm castings

Vermicompost is the product of composting utilizing various species of worms, usually red

wigglers, white worms, and earthworms to create a heterogeneous mixture of decomposing

vegetable or food waste (excluding meat, dairy, fats, or oils), bedding materials, and vermicast.

Vermicast, also known as worm castings, worm humus or worm manure, is the end-product of

the breakdown of organic matter by species of earthworm. Vermicomposting is widely used in

North America for on-site institutional processing of food waste, such as in hospitals and

shopping malls. This type of composting is sometimes suggested as a feasible indoor home

composting method. Vermicomposting has gained popularity in both these industrial and

domestic settings because, as compared to conventional composting, it provides a way to

compost organic materials more quickly (as defined by a higher rate of carbon-to-nitrogen ratio

increase) and to attain products that have lower salinity levels that are therefore more beneficial

to plant mediums.

The earthworm species (or composting worms) most often used are red wigglers ( Eisenia fetida

or Eisenia andrei), though European nightcrawlers ( Eisenia hortensis or Dendrobaena veneta)

could also be used. Red wigglers are recommended by most vermiculture experts, as they have

some of the best appetites and breed very quickly. Users refer to European nightcrawlers by a

variety of other names, including dendrobaenas, dendras, Dutch Nightcrawlers, and Belgian

nightcrawlers.

Containing water-soluble nutrients, vermicompost is a nutrient-rich organic fertilizer and soil

conditioner in a form that is relatively easy for plants to absorb. Worm castings are sometimesused as an organic fertilizer. Because the earthworms grind and uniformly mix minerals in

simple forms, plants need only minimal effort to obtain them. The worms' digestive systems also

add beneficial microbes to help create a "living" soil environment for plants.

Vermicompost tea in conjunction with 10% castings has been shown to cause up to a 1.7 times

growth in plant mass over plants grown without.



Researchers from the Pondicherry University discovered that worm composts can also be used to

clean up heavy metals. The researchers found substantial reductions in heavy metals when the

worms were released into the garbage and they are effective at removing lead, zinc, cadmium,

copper and manganese.

3.3.3 Incineration (h)

Incineration is a disposal method in which solid organic wastes are subjected to combustion so as

to convert them into residue and gaseous products. This method is useful for disposal of residue

of both solid waste management and solid residue from waste water management.This process

reduces the volumes of solid waste to 20 to 30 percent of the original volume. Incineration and

other high temperature waste treatment systems are sometimes described as "thermal treatment".

Incinerators convert waste materials into heat, gas, steam and ash.

Incineration is carried out both on a small scale by individuals and on a large scale by industry. It

is used to dispose of solid, liquid and gaseous waste. It is recognized as a practical method of

disposing of certain hazardous waste materials (such as biological medical waste). Incineration is

a controversial method of waste disposal, due to issues such as emission of gaseous pollutants.

Incineration is common in countries such as Japan where land is more scarce, as these facilities

generally do not require as much area as landfills. Waste-to-energy (WtE) or energy-from-waste

(EfW) are broad terms for facilities that burn waste in a furnace or boiler to generate heat, steam

or electricity. Combustion in an incinerator is not always perfect and there have been concerns

about pollutants in gaseous emissions from incinerator stacks. Particular concern has focused onsome very persistent organics such as dioxins, furans, PAHs which may be created which may

have serious environmental consequences.



3.3.4 Pyrolysis (h)

Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures in the

absence of oxygen (or any halogen). It involves the simultaneous change of chemical

composition and physical phase, and is irreversible. The word is coined from the Greek-derived

elements pyro "fire" and lysis "separating".

Pyrolysis is a type of thermolysis, and is most commonly observed in organic materials exposedto high temperatures. It is one of the processes involved in charring wood, starting at 200–300 °C

(390–570 °F),. It also occurs in fires where solid fuels are burning or when vegetation comes into

contact with lava in volcanic eruptions. In general, pyrolysis of organic substances produces gas

and liquid products and leaves a solid residue richer in carbon content, char. Extreme pyrolysis,

which leaves mostly carbon as the residue, is called carbonization.

The process is used heavily in the chemical industry, for example, to produce charcoal, activated

carbon, methanol, and other chemicals from wood, to convert ethylene dichloride into vinyl

chloride to make PVC, to produce coke from coal, to convert biomass into syngas and biochar, to

turn waste into safely disposable substances, and for transforming medium-weight hydrocarbonsfrom oil into lighter ones like gasoline. These specialized uses of pyrolysis may be called various

names, such as dry distillation, destructive distillation, or cracking.

Pyrolysis also plays an important role in several cooking procedures, such as baking, frying,

grilling, and caramelizing. In addition, it is a tool of chemical analysis, for example, in mass

spectrometry and in carbon-14 dating. Indeed, many important chemical substances, such as



phosphorus and sulfuric acid, were first obtained by this process. Pyrolysis has been assumed to

take place during catagenesis, the conversion of buried organic matter to fossil fuels. It is also the

basis of pyrography. In their embalming process, the ancient Egyptians used a mixture of

substances, including methanol, which they obtained from the pyrolysis of wood.

Pyrolysis differs from other high-temperature processes like combustion and hydrolysis in that it

usually does not involve reactions with oxygen, water, or any other reagents. In practice, it is not

possible to achieve a completely oxygen-free atmosphere. Because some oxygen is present in

any pyrolysis system, a small amount of oxidation occurs.

The term has also been applied to the decomposition of organic material in the presence of

superheated water or steam (hydrous pyrolysis), for example, in the steam cracking of oil.

Review Questions

1. Explain Properties of Solid Wastes.

2. Define Physical and chemical composition of municipal solid wastes.

3. Explain waste generation rates.

4. What is Management of Solid Wastes in India?

5. Describe Prevalent SWM practices and deficiencies.

6. Explain Disposal of Wastes.



Chaper-4

FIRE FIGHTING SERVICES (ch)

Structure of this unitFire, detectors

Learning Objectives1. Behaviour of fire

2. fire safety standards

3. concepts in fire protection

4.

Classification of buildings based on occupancy

5. fire fighting installation and requirements

6. Passive and active fire precautions

7.

site planning and fire brigade access8. Roof covering – control of fire spread

9. Heat sensitive detectors

10. smoke detectors

11. Automatic water system

12. Fire safety, fire & human behavior

13. Means of escape, design and planning of escape halts and corridors to final exit

4.1 Behaviour of fire (mh)

Fire Behaviour is the reaction of fire to the environment. A good understanding of bush fire

behaviour will facilitate better procedures and preparation for a bush fire event. The components

necessary for a fire to burn and continue to burn can be illustrated by the ‘fire triangle’.

The Fire Triangle

The behaviour of a fire is influenced by three main factors, namely fuel, weather and topography.

Fuel



Fuel is anything that will burn under suitable fire conditions. It rates as one of the most important

factors influencing the way a fire behaves and travels. Fuel is the common environmental factor

which is manipulated in order to modify fire behaviour. There are 4 variables of fuel that will

influence its contribution to fire behaviour. They are:

•

Type

• Size and quantity

• Arrangement

• Moisture

Weather

Weather is another major factor that will influence the spread of a fire. The four key elements of

weather that will influence fire behaviour are:

•

Air Temperature

• Relative humidity

• Wind

• Atmospheric stability

Effect of Wind on Fire Behaviour

Wind speed is the most important factor in determining fire behaviour in dry fuels. Wind acts on

a fire in the following ways:

1.

Tilts the flames forward and provides more effective radiation and pre-heating of the

unburnt fuels.

2.

Increases the chances of direct flame contact with fuels ahead of the fire

3. Maintains the oxygen supply to the combustion zone

4. Shifts the convection column ahead of the fire so that the convective energy of the fire

reinforces and increases the wind speed in the flame zone, providing additional

momentum to fire spread

5. Blows burning embers ahead of the fire to create spot fires.

Topography

The topography of the landscape also influence the speed at which a bush fire will spread

(referred to as the rate of spread). Fire will travel faster up-slope than down-slope and with

greater intensity because vegetation in front of the fire is pre-heated and will therefore more

readily ignite. This is an important factor in the rate and direction of fire spread and is usually

broken into three categories:



Slope

Slope is the steepness of the land and has the greatest influence on fire behaviour.

Aspect

Aspect is the direction the land faces - north, south, east or west. The aspect of a slope influences

a fire's behaviour in several ways

Terrain

Terrain or special land features may control wind flow in a relatively large area. Wind flows like

water in a stream and will try to follow the path of least resistance.

4.1.1 ignition (h)

An ignition system is a system for igniting a fuel-air mixture. Ignition systems are well known

in the field of internal combustion engines such as those used in petrol (gasoline) engines used to

power the majority of motor vehicles, but they are also used in many other applications such as

in oil-fired and gas-fired boilers, rocket engines, etc.

The first ignition system to use an electric spark was probably Alessandro Volta's toy electric

pistol from the 1780s. Virtually all petrol engines today use an electric spark for ignition.

Diesel engines rely on fuel compression for ignition, but usually also have glowplugs that

preheat the combustion chamber to allow starting of the engine in cold weather. Other enginesmay use a flame, or a heated tube, for ignition.

4.1.1.1 Modern ignition systems (sh)

The ignition system is typically controlled by a key operated Ignition switch.

Mechanically timed ignition



Distributor cap

Most four-stroke engines have used a mechanically timed electrical ignition system. The heart of

the system is the distributor. The distributor contains a rotating cam driven by the engine's drive,

a set of breaker points, a condenser, a rotor and a distributor cap. External to the distributor is the

ignition coil, the spark plugs and wires linking the distributor to the spark plugs and ignition coil.

The system is powered by a lead-acid battery, which is charged by the car's electrical system

using a dynamo or alternator. The engine operates contact breaker points, which interrupt the

current to an induction coil (known as the ignition coil).

The ignition coil consists of two transformer windings sharing a common magnetic core—the

primary and secondary windings. An alternating current in the primary induces alternating

magnetic field in the coil's core. Because the ignition coil's secondary has far more windings than

the primary, the coil is a step-up transformer which induces a much higher voltage across the

secondary windings. For an ignition coil, one end of windings of both the primary and secondary

are connected together. This common point is connected to the battery (usually through a

current-limiting ballast resistor). The other end of the primary is connected to the points within

the contact breaker. The other end of the secondary is connected, via the distributor cap and

rotor, to the spark plugs.



Ignition Circuit Diagram - Mechanically Timed Ignition

The ignition firing sequence begins with the points (or contact breaker) closed. A steady charge

flows from the battery, through the current-limiting resistor, through the coil primary, across the

closed breaker points and finally back to the battery. This steady current produces a magneticfield within the coil's core. This magnetic field forms the energy reservoir that will be used to

drive the ignition spark.

As the engine turns, so does the cam inside the distributor. The points ride on the cam so that as

the engine turns and reaches the top of the engine's compression cycle, a high point in the cam

causes the breaker points to open. This breaks the primary winding's circuit and abruptly stops

the current through the breaker points. Without the steady current through the points, the

magnetic field generated in the coil immediately and rapidly collapses. This change in the

magnetic field induces a high voltage in the coil's secondary windings.

At the same time, current exits the coil's primary winding and begins to charge up the capacitor

("condenser") that lies across the now-open breaker points. This capacitor and the coil’s primary

windings form an oscillating LC circuit. This LC circuit produces a damped, oscillating current

which bounces energy between the capacitor’s electric field and the ignition coil’s magnetic

field. The oscillating current in the coil’s primary, which produces an oscillating magnetic field

in the coil, extends the high voltage pulse at the output of the secondary windings. This high



voltage thus continues beyond the time of the initial field collapse pulse. The oscillation

continues until the circuit’s energy is consumed.

The ignition coil's secondary windings are connected to the distributor cap. A turning rotor,

located on top of the breaker cam within the distributor cap, sequentially connects the coil's

secondary windings to one of the several wires leading to each cylinder's spark plug. The

extremely high voltage from the coil's secondary (typically 20,000 to 50,000 volts) causes a

spark to form across the gap of the spark plug. This, in turn, ignites the compressed air-fuel

mixture within the engine. It is the creation of this spark which consumes the energy that was

stored in the ignition coil’s magnetic field.

The flat twin cylinder 1948 Citroën 2CV used one double ended coil without a distributor, and

just contact breakers, in a wasted spark system.

Some twin cylinder motorcycles and motor scooters had two contact points feeding twin coils

each connected directly to the spark plug without a distributor; eg the BSA Thunderbolt and

Triumph Tigress.

High performance engines with eight or more cylinders that operate at high r.p.m. (such as those

used in motor racing) demand both a higher rate of spark and a higher spark energy than the

simple ignition circuit can provide. This problem is overcome by using either of these

adaptations:

• Two complete sets of coils, breakers and condensers can be provided - one set for each

half of the engine, which is typically arranged in V-8 or V-12 configuration. Although the

two ignition system halves are electrically independent, they typically share a single

distributor which in this case contains two breakers driven by the rotating cam, and a

rotor with two isolated conducting planes for the two high voltage inputs.

• A single breaker driven by a cam and a return spring is limited in spark rate by the onset

of contact bounce or float at high rpm. This limit can be overcome by substituting for the breaker a pair of breakers that are connected electrically in series but spaced on opposite

sides of the cam so they are driven out of phase. Each breaker then switches at half the

rate of a single breaker and the "dwell" time for current buildup in the coil is maximized

since it is shared between the breakers. The Lamborghini V-12 engine has both these

adaptations and therefore uses two ignition coils and a single distributor that contains 4

contact breakers.



A distributor-based system is not greatly different from a magneto system except that more

separate elements are involved. There are also advantages to this arrangement. For example, the

position of the contact breaker points relative to the engine angle can be changed a small amount

dynamically, allowing the ignition timing to be automatically advanced with increasing

revolutions per minute (RPM) or increased manifold vacuum, giving better efficiency and

performance.

However it is necessary to check periodically the maximum opening gap of the breaker(s), using

a feeler gauge, since this mechanical adjustment affects the "dwell" time during which the coil

charges, and breakers should be re-dressed or replaced when they have become pitted by electric

arcing. This system was used almost universally until the late 1970s, when electronic ignition

systems started to appear.

Electronic ignition

The disadvantage of the mechanical system is the use of breaker points to interrupt the low-

voltage high-current through the primary winding of the coil; the points are subject to

mechanical wear where they ride the cam to open and shut, as well as oxidation and burning at

the contact surfaces from the constant sparking. They require regular adjustment to compensate

for wear, and the opening of the contact breakers, which is responsible for spark timing, is

subject to mechanical variations.

In addition, the spark voltage is also dependent on contact effectiveness, and poor sparking can

lead to lower engine efficiency. A mechanical contact breaker system cannot control an average

ignition current of more than about 3 A while still giving a reasonable service life, and this maylimit the power of the spark and ultimate engine speed.

Electronic ignition (EI) solves these problems. In the initial systems, points were still used but

they handled only a low current which was used to control the high primary current through a

solid state switching system. Soon, however, even these contact breaker points were replaced by

an angular sensor of some kind - either optical, where a vaned rotor breaks a light beam, or more

commonly using a Hall effect sensor, which responds to a rotating magnet mounted on the

distributor shaft. The sensor output is shaped and processed by suitable circuitry, then used to

trigger a switching device such as a thyristor, which switches a large current through the coil.



lack of moving parts compared with the mechanical system leads to greater reliability and longer

service intervals.

Chrysler introduced breakerless ignition in mid-1971 as an option for its 340 V8 and the 426

Street Hemi. For the 1972 model year, the system became standard on its high-performance

engines (the 340 cu in and the four-barrel carburetor-equipped 400 hp (298 kW) 400 cu in (7 l))

and was an option on its 318 cu in, 360 cu in , two-barrel 400 cu in (6.6 l), and low-performance

440 cu in. Breakerless Ignition was standardised across the model range for 1973.

For older cars, it is usually possible to retrofit an EI system in place of the mechanical one. In

some cases, a modern distributor will fit into the older engine with no other modifications, like

the H.E.I. distributor made by General Motors, the Hot-Spark electronic ignition conversion kit

and the aforementioned Chrysler-built electronic ignition system.

Other innovations are currently available on various cars. In some models, rather than one central

coil, there are individual coils on each spark plug, sometimes known as direct ignition or coil on

plug (COP). This allows the coil a longer time to accumulate a charge between sparks, and

therefore a higher energy spark. A variation on this has each coil handle two plugs, on cylinders

which are 360 degrees out of phase (and therefore reach TDC at the same time); in the four-cycle

engine this means that one plug will be sparking during the end of the exhaust stroke while the

other fires at the usual time, a so-called "wasted spark" arrangement which has no drawbacks

apart from faster spark plug erosion; the paired cylinders are 1/4 and 2/3. Other systems do away

with the distributor as a timing apparatus and use a magnetic crank angle sensor mounted on the

crankshaft to trigger the ignition at the proper time.

Digital electronic ignitions

At the turn of the 21st century digital electronic ignition modules became available for small

engines on such applications as chainsaws, string trimmers, leaf blowers, and lawn mowers. This

was made possible by low cost, high speed, and small footprint microcontrollers. Digital

electronic ignition modules can be designed as either capacitor discharge ignition (CDI) or

inductive discharge ignition (IDI) systems. Capacitive discharge digital ignitions store charged

energy for the spark in a capacitor within the module that can be released to the spark plug at

virtually any time throughout the engine cycle via a control signal from the microprocessor. This

allows for greater timing flexibility, and engine performance; especially when designed hand-in-hand with the engine carburetor.

Engine management

In an Engine Management System (EMS), electronics control fuel delivery and ignition timing.

Primary sensors on the system are crankshaft angle (crankshaft or Top Dead Center (TDC)



position), airflow into the engine and throttle position. The circuitry determines which cylinder

needs fuel and how much, opens the requisite injector to deliver it, then causes a spark at the

right moment to burn it. Early EMS systems used an analogue computer to accomplish this, but

as embedded systems dropped in price and became fast enough to keep up with the changing

inputs at high revolutions, digital systems started to appear.

Some designs using an EMS retain the original ignition coil, distributor and high-tension leads

found on cars throughout history. Other systems dispense with the distributor altogether and have

individual coils mounted directly atop each spark plug. This removes the need for both

distributor and high-tension leads, which reduces maintenance and increases long-term

reliability.

Modern EMSs read in data from various sensors about the crankshaft position, intake manifold

temperature, intake manifold pressure (or intake air volume), throttle position, fuel mixture via

the oxygen sensor, detonation via a knock sensor, and exhaust gas temperature sensors. The

EMS then uses the collected data to precisely determine how much fuel to deliver and when and

how far to advance the ignition timing. With electronic ignition systems, individual cylinders

can have their own individual timing so that timing can be as aggressive as possible per cylinder

without fuel detonation. As a result, sophisticated electronic ignition systems can be both more

fuel efficient, and produce better performance over their counterparts.

4.1.2 igniter (h)

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4.1.3 Combustible contents (h)

Combustibility is a measure of how easily a substance will set on fire, through fire or

combustion. This is an important property to consider when a substance is used for construction

or is being stored. It is also important in processes that produce combustible substances as a by- product. Special precautions are usually required for substances that are easily combustible.

These measures may include installation of fire sprinklers or storage remote from possible

sources of ignition.

Substances with low combustibility may be selected for construction where the fire risk needs to

be reduced.Like apartment buildings, houses,offices and so on. If combustible resources are used



there is greater chance of fire accidents and deaths. Fire resistant substances are preferred for

building materials and furnishings.

Code Definitions

For an Authority Having Jurisdiction, combustibility is defined by the local code. In the National

Building Code of Canada, it is defined as follows:

•

Combustible: A material which fails to meet acceptance criteria of CAN/ULC-S114,

Standard Method of Test for Determination of Noncombustibility in Building Materials.

This leads to the definition of noncombustible:

• Non-combustible: means that a material meets the acceptance criteria of CAN4-S114,

"Standard Method of Test for Determination of Non-Combustibility in Building

Materials".

4.1.3.1 Fire testing (sh)

Various countries have tests for determining noncombustibility of materials. Most involve the

heating of a specified quantity of the test specimen for a set duration. Usually, the material

cannot support combustion and must not undergo a certain loss of mass. As a rule of thumb,

concrete, steel, ceramics, in other words inorganic substances pass these tests, which permits

them to be mentioned in building codes as being suitable and sometimes even mandated for use

in certain applications. In Canada, for instance, firewalls must be made of concrete.



4.1.3.2 Relevance in construction (sh)

In building construction, buildings are typically divided into combustible and noncombustible

ones. The code provisions and safety measures that must be taken into account in the design and

construction of a building depend to a significant extent upon whether the structure is made from

noncombustible elements, such as concrete, brick and structural steel, or a combustible element

such as wood. Combustible structures have more stringent limits on maximum building height

and area.

4.1.3.3 Combustible dust (sh)

A number of industrial processes produce combustible dust as a by-product. The most common

being wood dust. Combustible dust has been defined as: a solid material composed of distinct

particles or pieces, regardless of size, shape, or chemical composition, which presents a fire or

deflagration hazard when suspended in air or some other oxidizing medium over a range of

concentrations. In addition to wood, combustible dusts include metals, especially magnesium

and aluminum, as well as other carbon-based dusts. There are at least a 140 known substances

that produce combustible dust. While the particles in a combustible dusts may be of any size,

normally they have a diameter of less than 420 µm. As of 2012, the United States Occupational

Safety and Health Administration has yet to adopt a comprehensive set of rules on combustible

dust.

When suspended in air (or any oxidizing environment), the fine particles of combustible dust

present a potential for explosions. Accumulated dust, even when not suspended in air, remains a

fire hazard. The National Fire Protection Association (U.S.) specifically addresses the preventionof fires and dust explosions in agricultural and food products facilities in NFPA Code section 61,

and other industries in NFPA Code sections 651–664. Collectors designed to reduce airborne

dust account for more than 40 percent of all dust explosions. Other important processes are

grinding and pulverizing, transporting powders, filing silos and containers (which produces

powder), and the mixing and blending of powders.

Investigation of 200 dust explosions and fires, between 1980 to 2005, indicated approximately

100 fatalities and 600 injuries. In January 2003, a polyethylene powder explosion and fire at the

West Pharmaceutical Services plant in Kinston, North Carolina resulted in the deaths of six

workers and injuries to 38 others. In February 2008 an explosion of sugar dust rocked theImperial Sugar Company's plant at Port Wentworth, Georgia, resulting in thirteen deaths.

Related matters

The flammability article describes further the subcategorisations of combustible matters. Here,

further fire tests are involved in quantifying the degree of flammability or combustibility.



The chemistry underlying the fire testing and resulting code classifications

The degree of flammability or combustibility depends largely upon the chemical composition of

the subject material, as well as the ratio of mass versus surface area. As an example, paper is

made from wood. A piece of paper catches on fire quite easily, whereas a heavy oak desk is

much harder to ignite, although the wood fibre is the same in each substance, be it a piece of

paper or a wooden board. Also, Antoine Lavoisier's law of conservation of mass, states that

matter can be neither created nor destroyed, only altered. Therefore, the combustion or burning

of a substance causes a chemical change, but does not decrease the mass of the original matter.

The mass of the remains (ash, water, carbon dioxide, and other gases) is the same as it was prior

to the burning of the matter. Whatever is not left behind in ashes and remains, literally went up in

smoke, but it all went somewhere and the atoms of which the substance consisted before the fire

still exist after the fire, even though they may be present in other phases and molecules.

4.1.4 causes of fire (h)

The fire season generally runs from April to October, with the peak of activity occurring from

mid-May to August. Catastrophic fires tend to occur during periods of extended drought or wind

storms.

Lightning strikes cause slightly less than half of all wildland fires in Canada, but account for

nearly 67% of the land area burned. There are two main reasons for this:

• Lightning-caused fires often occur in remote areas where human life, property and timber

values are not threatened. Fire suppression in these areas may therefore be intentionally

limited, leaving fire to play its natural role.

• Several lightning fires can be ignited simultaneously, leaving agencies with difficult

decisions about where to send available firefighting crews and equipment.

Humans cause slightly more than half of all wildland fires in Canada, typically in populated

forest and grassland areas. Because of where these fires occur, they are usually spotted early and

can be reached quickly by firefighting crews. Still, the threat they pose to human safety and

property makes them a major concern for firefighting crews.

4.1.5 Mechanism of fire spread in building and prevention (h)

Fire protection is the study and practice of mitigating the unwanted effects of potentially

destructive fires.[1] It involves the study of the behaviour, compartmentalisation, suppression and

investigation of fire and its related emergencies, as well as the research and development,



production, testing and application of mitigating systems. In structures, be they land-based,

offshore or even ships, the owners and operators are responsible to maintain their facilities in

accordance with a design-basis that is rooted in laws, including the local building code and fire

code, which are enforced by the Authority Having Jurisdiction. Buildings must be constructed in

accordance with the version of the building code that is in effect when an application for a

building permit is made. Building inspectors check on compliance of a building under

construction with the building code. Once construction is complete, a building must be

maintained in accordance with the current fire code, which is enforced by the fire prevention

officers of a local fire department. In the event of fire emergencies, Firefighters, fire

investigators, and other fire prevention personnel called to mitigate, investigate and learn from

the damage of a fire. Lessons learned from fires are applied to the authoring of both building

codes and fire codes.

In the United States, this term is used by engineers and code officials when referring only to

active and passive fire protection systems, and does usually not encompass fire detection systemssuch as fire alarms or smoke detection.

Public sign warning of the highest level of fire hazard at a campsite in Germany

fire prevention and control, the prevention, detection, and extinguishment of fires, including

such secondary activities as research into the causes of fire, education of the public about fire

hazards, and the maintenance and improvement of fire-fighting equipment.

4.1.5.1 Goals (sh)

Fire protection has three major goals:



• Continuity of operations - on a public scale, this is intended to prevent the interruption

of critical services necessary for the public welfare (e.g., a 911 emergency call center).

• Property protection - on a public scale, this is intended to prevent area wide

conflagrations. At an individual building level, this is typically an insurance

consideration (e.g., a requirement for financing), or a regulatory requirement.

• Life safety - the minimum standard used in fire and building codes

4.1.5.2 Classifying fires (sh)

When deciding on what fire protection is appropriate for any given situation, it is important to

assess the types of fire hazard that may be faced.

Some jurisdictions operate systems of classifying fires using code letters. Whilst these may agree

on some classifications, they also vary. Below is a table showing the standard operated in Europe

and Australia against the system used in the United States.

Type of Fire Australia EuropeanNorthAmerica

Fires that involve flammable solids such as wood,

cloth, rubber, paper, and some types of plastics.Class A Class A Class A

Fires that involve flammable liquids or liquefiable

solids such as petrol/gasoline, oil, paint, some waxes

& plastics, but not cooking fats or oils

Class B Class B

Class B

Fires that involve flammable gases, such as natural

gas, hydrogen, propane, butaneClass C Class C

Fires that involve combustible metals, such as

sodium, magnesium, and potassiumClass D Class D Class D

Fires that involve any of the materials found in

Class A and B fires, but with the introduction of anelectrical appliances, wiring, or other electrically

energized objects in the vicinity of the fire, with a

resultant electrical shock risk if a conductive agent

is used to control the fire.

Class E1

(Class E) nowno longer in the

European

standards

Class C



Fires involving cooking fats and oils. The high

temperature of the oils when on fire far exceeds that

of other flammable liquids making normal

extinguishing agents ineffective.

Class F Class F Class K

Technically there is no such thing as a "Class E" fire, as electricity itself does not burn. However

it is considered a dangerous and very deadly complication to a fire, therefore using the incorrect

extinguishing method can result in serious injury or death. Class E, however generally refers to

fires involving electricity, therefore a bracketed E, "(E)" denoted on various types of

extinguishers.

Fires are sometimes categorized as "one alarm", "two alarm", "three alarm" (or higher) fires.

There is no standard definition for what this means quantifiably, though it always refers to the

level response by the local authorities. In some cities, the numeric rating refers to the number of

fire stations that have been summoned to the fire. In others, the number counts the number of

"dispatches" for additional personnel and equipment.

4.1.5.3 Components (sh)

Structural fire protection (in land-based buildings, offshore construction or onboard ships) is

typically achieved via three means:

• Passive fire protection (use of integral, fire-resistance rated wall and floor assemblies that

are used to form fire compartments intended to limit the spread of fire, or occupancy

separations, or firewalls, to keep fires, high temperatures and flue gases within the fire

compartment of origin, thus enabling firefighting and evacuation)

• Active fire protection (manual and automatic detection and suppression of fires, as in

using and installing a fire sprinkler system or finding the fire (fire alarm) and/or

extinguishing it)

• Education (ensuring that building owners and operators have copies and a working

understanding of the applicable building and fire codes, having a purpose-designed fire

safety plan and ensuring that building occupants, operators and emergency personnel

know the building, its means of Active fire protection and Passive fire protection, its

weak spots and strengths to ensure the highest possible level of safety)

4.1.5.4 Balanced Approach (sh)

Passive fire protection (PFP) in the form of compartmentalisation was developed prior to the

invention of or widespread use of active fire protection (AFP), mainly in the form of automatic

fire sprinkler systems. During this time, PFP was the dominant mode of protection provided in



facility designs. With the widespread installation of fire sprinklers in the past 50 years, the

reliance on PFP as the only approach was reduced. Lobby groups are typically divided into two

camps favouring active or passive fire protection. Each camp tries to garner more business for

itself through its influence in establishing or changing local and national building and fire codes.

At present, the camp favouring AFP appears to be leading, because of the factors mentioned

above.

The relatively recent inclusion of performance based or objective based codes, which have a

greater emphasis on life safety than property protection, tend to support AFP initiatives, and can

lead to the justification for a lesser degree of fire resistant rated construction. At times it works

the other way around, as firewalls that protrude through the roof structure are used to "sub-

divide" buildings such that the separated parts are of smaller area and contain smaller fire

hazards, and do not necessarily require sprinklers.

The decision to favour AFP versus PFP in the design of a new building may be affected by the

lifecycle costs. Lifecycle costs can be shifted from capital to operational budgets and vice versa.

4.1.5.5 Building Operation in conformance with Design (sh)

The building is designed in compliance with the local building code and fire code by the

architect and other consultants. A building permit is issued after review by the Authority Having

Jurisdiction (AHJ).

Deviations from that original plan should be made known to the AHJ to make sure that the

change is still in compliance with the law to prevent any unsafe conditions that may violate the

law and put people at risk. For example, if the firestop systems in a structure were inoperable, a

significant part of the fire safety plan would not work in the event of a fire because the walls and

floors that contain the firestops are intended to have a fire-resistance rating, which has been

achieved through passing a fire test and, often, product certification of the components involved

in the construction of those walls and floors. Likewise, if the sprinkler system or fire alarm

system is inoperable for lack of knowledgeable maintenance, or if the building occupants prop

open a fire door and then run a carpet through, the likelihood of damage and casualties is

increased. It is vital for everyone to realise that fire protection within a structure is a system that

relies on all of its components.

4.2 fire safety standards (mh)

(a) All development subject to the provisions of this article shall be constructed and maintained

in compliance with the standards specified in this article. Approvals and permits for any



development may be withheld or refused until adequate provision has been made to ensure such

compliance.

(b) Exceptions to the standards specified in this article and mitigated practices may be allowed

where the exception or mitigated practice provides the same overall practical effect as the

specified standards.

(c) Application for an exception or mitigated practice shall be made in writing by an applicant

for development or the applicant's authorized representative. The application shall state the

specific section or sections of this article for which an exception or mitigated practice is

proposed, material facts supporting the contention of the applicant, the details of the exception or

mitigated practice proposed, and a map showing the proposed location and setting of the

exception or mitigated practice. The burden of proving that a proposed exception or mitigated

practice is warranted shall be on the applicant.

(d) The County Fire Chief shall determine whether to grant, deny, or modify any application for

an exception or mitigated practice filed in connection with the issuance of any building permit.

The planning commission, board of zoning adjustments, project review and advisory committee,or design review committee shall determine whether to grant, deny, or modify any application

for an exception or mitigated practice filed in connection with any development approval under

their respective jurisdictions. Modification of an application for an exception or mitigated

practice by the County Fire Chief, planning commission, board of zoning adjustments, project

review and advisory committee, or design review committee shall be limited to the alternate fire

protection measures specified.

(e) Where an application for an exception or mitigated practice is denied or modified, the

applicant may appeal such denial or modification. Appeal from a denial or modification by the

County Fire Chief shall be made pursuant to Article III of this chapter. Appeal from a denial or

modification by the planning commission, board of zoning adjustments, project review andadvisory committee, or design review committee shall be made of this Code, as appropriate. In

order to grant an appeal, the body hearing the appeal must find that the exception or mitigated

practice proposed meets the intent of this article.

(f) A written copy of any decision granting an appeal within a state responsibility area shall be

provided to the director of forestry and fire protection within ten (10) days after the decision is

final.

4.2.1 Scope of coverage (h)

(a) The provisions of this article shall apply to all development on all lands within the

unincorporated area of the county.

(b) Except as otherwise provided in this article, all applications for development approvals shall

be accompanied by plans, engineering calculations, and other data necessary to determine

compliance with the provisions of this article.



(c) Except as otherwise provided in this article, compliance with the provisions of this article

shall occur prior to the commencement of construction of any structure unless otherwise

authorized by the County Fire Chief.

4.2.2 Exemptions (h)

The provisions of this article shall not apply to any of the following, except to the

extent provided for herein:

(a) Any building granted an agricultural exemption, provided that the building does not exceed

8,000 square feet in size and is not located in a state responsibility area.

(b) Any road or bridge used exclusively for access to an agricultural operation; or an agricultural

exempt structure; or a Group U, Occupancy accessory to a one- or two-family residential

dwelling, as defined in the County Building Code, that is under less than1,000 square feet in

area.

(c) Any road or bridge used exclusively for the management and harvesting of wood products.

(d) Any new building having a floor area of less than six hundred forty (640) square feet and

containing an occupancy other than a detached Group U Occupancy as defined in the County

Building Code, except that the provisions of Divisions C and E of this article shall apply to all

such buildings.

(e) Any new building accessory to a one-or two-family residential dwelling with a floor area of

less than one thousand (1,000) square feet and containing a detached Group U Occupancy as

defined in the County Building Code, except that the provisions of Divisions C and E of this

article shall apply to all such buildings.

(f) Any existing road that provides year-round unobstructed access to conventional drivevehicles, including sedans and fire engines, which was constructed and serving a legal parcel

prior to January 1, 1992, except that

(1) the provisions of Division C of this article shall apply to all such roads, and

(2) all of the other provisions of this article shall apply to any such road if it is extended,

reconstructed or improved pursuant to a development approval, but only to the portion of the

road that is extended, reconstructed or improved.

(g) Any road required as a condition of any development approval granted prior to January 1,

1992, except that


(2) all of the other provisions of this article shall apply to any such road if it is extended,reconstructed or improved pursuant to a new development approval, but only to the portion of

the road that is extended, reconstructed or improved.

(h) Any driveway serving a legally constructed residential building prior to January 1, 1992,

except that




(2) all of the other provisions of this article shall apply to any such driveway if it is extended,

reconstructed or improved pursuant to a new development approval, but only to the portion of

the driveway that is extended, reconstructed or improved.

(i) Any legal or legal non-conforming building constructed prior to January 1, 1992, or any

building for which a building permit was issued or an application for a building permit was

accepted as complete for filing prior to January 1, 1992; except that the provisions of this article

shall apply to any such building if the occupancy is changed, altered, or otherwise converted to

any Group R, Division 3 occupancy as defined in the County Building Code.

(j) Any addition to an existing building adding a floor area less than six hundred forty (640)

square feet including a detached Group U Occupancy as defined in the County Building Code,

except that the provisions of Divisions C and E of this article shall apply to all such buildings.

4.2.3 Administration and enforcement – Inspections (h)

(a) The administration and enforcement of the provisions of this article shall be the shared

responsibility of the County Fire Chief and the Director of Permit and Resource Management.

(b) Inspections to determine compliance with the provisions of this article shall be the

responsibility of the County Fire Chief or the Director of Permit and Resource Management, as

appropriate. The County Fire Chief or the Director of Permit and Resource Management may

authorize a local fire chief to conduct inspections within a local fire protection district under the

direction of the County Fire Chief or the Director of Permit and Resource Management. In such

cases, inspection results shall be provided to the County Fire Chief or the Director of Permit and

Resource Management promptly after completion of the inspection.

4.3 concepts in fire protection (mh)

Safety through technology: Minimax has been one of the leading companies in the fire protection

industry for more than 100 years and now many of their innovative products are available in

North America.

Minimax detects fires at an early stage.

Safe and fast fire detection is an essential component of a reliable fire protection concept. The

earlier a fire is detected, the smaller are the dangers and damages caused by the fire. Here,

customized planning is of special importance. The cooperation of fire protection control panel,

detectors and alarms facilitates a fast reaction in case of fire - ideally, by automatic activation of

an extinguishing system. In this way you will have the situation under control immediately

Minimax offers low-impact extinguishing technology.

Sensitive technologies, objects and areas need a special protection scheme. Minimax has the

right solution. Our gaseous extinguishing agents are environmentally safe and provide fast,



reliable protection of human life and material assets. Specially adapted to the individual

application, they fight fires with no side effects or negative impact on the protected objects

4.3.1 Our services at a glance (h)

Fire protection concepts and assessments

• Comprehensive and protection goal-oriented fire protection concepts

• Fire protection assessments for existing buildings and fire protection concepts to be

submitted

• Certificates according to engineering fire protection methods

• Weak spot analyses and restoration concepts taking into consideration risk-oriented

parameters and economic feasibility

Fire protection planning

• Advice from planners, architects, and builders, e.g. in the practical implementation of fire

protection concepts

• Measurement of individual components for fire drills

• Measurement of plant-specific fire protection measures, e.g. smoke and heat extraction

systems, extinguishing systems, and fire fighting water containment systems

• Use of scientifically secured calculation methods for verification management, e.g. fire

simulators for fire and smoke proliferation, evacuation calculations, and measurements of

components

Monitoring

• Monitoring during construction as well as an acceptance inspection of fire protection

measures at the construction site

• Acceptance and function inspections as well as recurring testing of plant-specific fire

protection measures

• Provision of supervisory engineers specialising in fire protection

Object consultation

• Fire protection assessments and preparation of priority lists for risk-oriented remedial

work

• Preparation of fire protection documentation, e.g. fire protection ordinances, escape and

rescue plans, fire brigade plans, fire protection plans



• Provision of fire protection representatives

4.4 Classification of buildings based on occupancy (mh)

Building occupancy classifications refer to categorizing structures based on their usage and are primarily used for building and fire code enforcement. They are usually defined by model

building codes, and vary, somewhat, among them. Often, many of them are subdivided. The

following is based on the International Building Code, the most commonly used building code in

the United States:

• Assembly (Group A) - places used for people gathering for entertainment, worship, and

eating or drinking. Examples: churches, restaurants (with 50 or more possible occupants),

theaters, and stadiums.

• Business (Group B) - places where services are provided (not to be confused with

mercantile, below). Examples: banks, insurance agencies, government buildings

(including police and fire stations), and doctor's offices.

• Educational (Group E) - schools and day care centers up to the 12th grade.

• Factory (Group F) - places where goods are manufactured or repaired (unless considered

"High-Hazard" (below)). Examples: factories and dry cleaners.

• High-Hazard (Group H) - places involving production or storage of very flammable or

toxic materials. Includes places handling explosives and/or highly toxic materials (such

as fireworks, hydrogen peroxide, and cyanide).

• Institutional (Group I) - places where people are physically unable to leave without

assistance. Examples: hospitals, nursing homes, and prisons. In some jurisdictions, GroupI may be used to designate Industrial.

• Mercantile (Group M) - places where goods are displayed and sold. Examples: grocery

stores, department stores, and gas stations.

• Residential (Group R) - places providing accommodations for overnight stay (excluding

Institutional). Examples: houses, apartment buildings, hotels, and motels.

• Storage (Group S) - places where items are stored (unless considered High-Hazard).

Examples: warehouses and parking garages.

• Utility and Miscellaneous (Group U) - others. Examples: water towers, barns, towers.

Many buildings may have multiple occupancies. These are referred to as "mixed occupancies"and the different parts will be required to meet the codes for those specific areas. An example of

this is a shopping mall with underground parking. The shopping area itself is Group M

(mercantile), while the parking area would qualify as Group S (storage).

In places where more than one occupancy may apply the stricter code is usually enforced. An

example of this is a restaurant with seating under 50 which is not addressed in the code as either



mercantile or business (this is a technical issue, but could be viewed as either or neither). Code

enforcement officials will usually enforce the strictest side of the code.

Occupancy or use categories. Every new and existing building, structure or part thereof shall,

for the purpose of this code, be classified according to its use or occupancy as a building or

structure of one of the following occupancy groups:

Group A -Assembly

Group B -Business

Group D -Day Care

Group E -Educational

Group F -Factory Industrial

Group H -Hazardous

Group I -Institutional

Group M -Mercantile

Group R -ResidentialGroup S -Storage

4.5 fire fighting installation and requirements (mh)

4.5.1 PROCEDURE FOR CLEARANCE FROM FIRE SERVICE (h)

a) The concerned Authority shall refer the building plans to the Chief Fire Officer.

b) The Authority shall furnish three sets of complete building plans along with prescribed fee to

the Chief Fire Officer, after ensuring that the proposals are in line with Master Plan/ZonalPlan of the area.

c) The plans shall be clearly marked and indicate the complete fire protection arrangements.

d) The Chief Fire Officer shall examine these plans to ensure that they are in accordance with the

provisions of fire safety and means of escape as per these bye- laws and shall forward

two sets of plans duly signed for implementation to the building sanctioning Authority.

e) After completion of firefighting installations as approved and duly tested and certified by the

licensed Fire Consultant / Architect, the Owner/ Builder of the building shall approach

the Chief Fire Officer through the concerned Authority for obtaining clearance from fire

safety and means of escape point of view.

f) On receipt of the above request, the Chief Fire Officer shall issue the No Objection Certificate

from fire safety and means of escape point of view after satisfying himself that the entire

fire protection measures are implemented and functional as per approved plans.

g) Any deficiencies observed during the course of inspection shall be communicated to the

Authority for rectification and a copy of the same shall be forwarded to the concerned

building owner /builder.



4.5.2 RENEWAL OF FIRE CLEARANCE (h)

On the basis of undertaking given by the Fire Consultant / Architect, the Chief Fire Officer shall

renew the fire clearance in respect of the following buildings on annual basis:-

1) Public entertainment and assembly

2) Hospitals

3) Hotels

4) Underground shopping complex

4.5.3 FIRE PROTECTION REQUIREMENTS (h)

Buildings shall be planned, designed and constructed to ensure fire safety and this sha1l be done

in accordance with part IV Fire Protection of National Building Code of India, unless otherwise

specified in these Bye-Laws. In the case of buildings the building schemes shall also be cleared

by the Chief Fire Officer.

4.5.3.1 First Aid /Fixed Fire Fighting /Fire Detection Systems and other Facilities (sh)

Provision of fire safety arrangement for different occupancy from. SI no. 1 to 23 as indicated

below shall be as per Annexure 'A' 'B' & 'C'.

1. Access

2. Wet Riser

3. Down Comer

4. Hose Reel

5. Automatic Sprinkler System6. Yard Hydrant

7. U.G. Tank with Draw off Connection

8. Terrace Tanks

9. Fire Pump

10. Terrace Pump

11. First Aid Fire Fighting Appliances

12. Auto Detection System

13. Manual operated Electrical Fire Alarm System

14. P.A System with talk back facility

15. Emergency Light

16. Auto D.G. Set

17. Illuminated Exit Sign

18. Means of Escape

19. Compartimentation

20. MCB /ELCB



21. Fire Man Switch in Lift

22. Hose Boxes with Delivery Hoses and Branch

23. Pipes Refuge Area

Note for Annexure ‘A’ ‘B’ & ‘C’1 Where more than one riser is required because of large floor area, the quantity of water

and pump capacity recommended in these Annexures should be finalized in

consultation with Chief Fire Officer.

2 The above quantities of water shall be exclusively for fire fighting and shall not be

utilized for domestic or other use.

3 A facility to boost up water pressure in the riser directly from the mobile pump shall be

provided in the wet riser, down comer system with suitable fire service inlets

(collecting head) with 2 to 4 numbers of 63 mm inlets for 100-200 mm dia main,

with check valve and a gate valve.

4. Internal diameter of rubber hose for reel shall be minimum 20 mm. A shut off branch

with nozzle of 5 mm. size shall be provided.5 Fire pumps shall have positive suctions. The pump house shall be adequately ventilated

by using normal/mechanical means. A clear space of 1.0 m. shall be kept in

between the pumps and enclosure for easy movement /maintenance. Proper

testing facilities and control panel etc. shall be provided. 6 Unless otherwise

specified in Bye-Laws, the fire fighting equipments /installation shall conform to

relevant Indian Standard Specification.

7 In case of mixed occupancy, the fire fighting arrangement shall be made as per the

highest class of occupancy.

8 Requirement of water based first aid fire extinguishers shall be reduced to half if hose

reel is provided in the Building.

4.6 Passive and active fire precautions (mh)

4.6.1 Passive fire protection (h)

Fire-resistance rated wall assembly with fire door, cable tray penetration and intumescent cable

coating.



Passive fire protection (PFP) is an integral component of the three components of structural fire

protection and fire safety in a building. PFP attempts to contain fires or slow the spread, through

use of fire-resistant walls, floors, and doors (amongst other examples). PFP systems must comply

with the associated Listing and approval use and compliance in order to provide the effectiveness

expected by building codes.

4.6.1.1 Structural fire protection (sh)

Fire protection in a building, offshore facility or a ship is a system that includes:

• Active fire protection, which can include manual or automatic fire detection and fire

suppression.

• Passive fire protection, which includes compartmentalisation of the overall building

through the use of fire-resistance rated walls and floors. Organization into smaller fire

compartments, consisting of one or more rooms or floors, prevents or slows the spread of

fire from the room of fire origin to other building spaces, limiting building damage and

providing more time to the building occupants for emergency evacuation or to reach an

area of refuge.

• Fire prevention includes minimizing ignition sources, as well as educating the occupants

and operators of the facility, ship or structure concerning operation and maintenance of

fire-related systems for correct function, and emergency procedures including notification

for fire service response and emergency evacuation.

4.6.1.2 Main characteristics (sh)

The aim for passive fire protection systems is typically demonstrated in fire testing the ability to

maintain the item or the side to be protected at or below either 140 °C (for walls, floors and

electrical circuits required to have a fire-resistance rating) or ca. 550 °C, which is considered the

critical temperature for structural steel, above which it is in jeopardy of losing its strength,

leading to collapse. This is based, in most countries, on the basic test standards for walls and

floors. Smaller components, such as fire dampers, fire doors, etc., follow suit in the main

intentions of the basic standard for walls and floors. Fire testing involves live fire exposures

upwards of 1100 °C, depending on the fire-resistance rating and duration one is after. More items

than just fire exposures are typically required to be tested to ensure the survivability of the

system under realistic conditions.

To accomplish these aims, many different types of materials are employed in the design and

construction of systems. For instance, common endothermic building materials include calcium

silicate board, concrete and gypsum wallboard. During fire testing of concrete floor slabs, water

can be seen to boil out of a slab. Gypsum wall board typically loses all its strength during a fire.

The use of endothermic materials is established and proven to be sound engineering practice.



The chemically bound water inside these materials sublimes. During this process, the unexposed

side cannot exceed the boiling point of water. Once the hydrates are spent, the temperature on the

unexposed side of an endothermic fire barrier tends to rise rapidly. Too much water can be a

problem, however. Concrete slabs that are too wet, will literally explode in a fire, which is why

test laboratories insist on measuring water content of concrete and mortar in fire test specimens,

before running any fire tests. PFP measures can also include intumescents and ablative materials.

The point is, however, that whatever the nature of the materials, they on their own bear no rating.

They must be organised into systems, which bear a rating when installed in accordance with

certification listings or established catalogues, such as DIN 4102 Part 4 or the Canadian National

Building Code.

Passive Fire Protection measures are intended to contain a fire in the fire compartment of origin,

thus limiting the spread of fire and smoke for a limited period of time, as determined the local

building code and fire code. Passive fire protection measures, such as firestops, fire walls, and

fire doors, are tested to determine the fire resistance rating of the final assembly, usuallyexpressed in terms of hours of fire resistance (e.g., ⅓, ¾, 1, 1½, 2, 3, 4 hour). A certification

listing provides the limitations of the rating.

Contrary to active fire protection measures, passive fire protection means do not typically require

electric or electronic activation or a degree of motion. Exceptions to that particular rule of thumb

are fire dampers (fire-resistive closures within air ducts, excluding grease ducts) and fire door

closers, which must move, open and shut in order to work, as well as all intumescent products,

which swell, thus move, in order to function.

As the name suggests, passive fire protection (PFP) remains silent in your coating system till theeventuality of a fire. There are mainly two types of PFP : intumescent fire protection and

vermiculite fire protection. In vermiculite fire protection, the structural steel members are

covered with vermiculite materials, mostly a very thick layer. This is a cheaper option as

compared to an intumescent one, but is very crude and aesthetically unpleasant. Moreover if the

environment is corrosive in nature, then the vermiculite option is not advisable, as there is the

possibility of water seeping into it (because of the porous nature of vermiculite), and there it is

difficult to monitor for corrosion. Intumescent fireproofing is a layer of paint which is applied

along with the coating system on the structural steel members. The thickness of this intumescent

coating is dependent on the steel section used. For calculation of DFT (dry film thickness) a

factor called Hp/ A (heated perimeter divided by cross sectional area), referred to as "sectionfactor" and expressed in m

-1, is used. Intumescent coatings are applied as an intermediate coat in

a coating system (primer, intermediate, and top/finish coat). Because of the relatively low

thickness of this intumescent coating (usually in the 350- to 700-micrometer range), nice finish,

and anti-corrosive nature, intumescent coatings are preferred aesthetically and performance-wise.



It should be noted that in the eventuality of a fire, the steel structure will eventually collapse once

the steel attains the critical core temperature (around 550 degrees Celsius or 850 degrees

Fahrenheit). The PFP system will only delay this by creating a layer of char between the steel

and fire. Depending upon the requirement, PFP systems can provide fire ratings in excess of 120

minutes. PFP systems are highly recommended in infrastructure projects as they can save lives

and property.

PFP in a building can be described as a group of systems within systems. An installed firestop,

for instance, is a system that is based upon a product certification listing. It forms part of a fire-

resistance rated wall or floor, and this wall or floor forms part of a fire compartment which forms

an integral part of the overall fire safety plan of the building. The building itself, as a whole, can

also be seen as a system.

4.6.1.3 Examples (sh)

This I beam has a fireproofing material sprayed onto it as a form of passive fire protection.

• fire-resistance rated walls

• Firewalls not only have a rating, they are also designed to sub-divide buildings such that

if collapse occurs on one side, this will not affect the other side. They can also be used to

eliminate the need for sprinklers, as a trade-off.

• Fire-resistant glass glass using multi-layer intumescent technology or wire mesh

embedded within the glass may be used in the fabrication of fire-resistance rated

windows in walls or fire doors.• fire-resistance rated floors

• occupancy separations (barriers designated as occupancy separations are intended to

segregate parts of buildings, where different uses are on each side; for instance,

apartments on one side and stores on the other side of the occupancy separation).

• closures (fire dampers) Sometimes firestops are treated in building codes identically to

closures. Canada de-rates closures, where, for instance a 2 hour closure is acceptable for



use in a 3 hour fire separation, so long as the fire separation is not an occupancy

separation or firewall. The lowered rating is then referred to as a fire protection rating,

both for firestops, unless they contain plastic pipes and regular closures.

• firestops

• grease ducts (These refer to ducts that lead from commercial cooking equipment such as

ranges, deep fryers and double-decker and conveyor-equipped pizza ovens to grease duct

fans.) In North America, grease ducts are made of minimum 16 gauge (1.6 mm) sheet

metal, all welded, and certified openings for cleaning, whereby the ducting is either

inherently manufactured to have a specific fire-resistance rating, OR it is ordinary 16

gauge ductwork with an exterior layer of purpose-made and certified fireproofing. Either

way, North American grease ducts must comply with NFPA96 requirements.

• cable coating (application of fire-retardants, which are either endothermic or

intumescent, to reduce flamespread and smoke development of combustible cable-

jacketing)

•

spray fireproofing (application of intumescent or endothermic paints, or fibrous orcementitious plasters to keep substrates such as structural steel, electrical or mechanical

services, valves, liquefied petroleum gas (LPG) vessels, vessel skirts, bulkheads or decks

below either 140 °C for electrical items or ca. 500 °C for structural steel elements to

maintain operability of the item to be protected)

• fireproofing cladding (boards used for the same purpose and in the same applications as

spray fireproofing) Materials for such cladding include perlite, vermiculite, calcium

silicate, gypsum, intumescent epoxy, Durasteel (cellulose-fibre reinforced concrete and

punched sheet-metal bonded composite panels), MicroTherm

• enclosures (boxes or wraps made of fireproofing materials, including fire-resistive wraps

and tapes to protect speciality valves and other items deemed to require protection againstfire and heat—an analogy for this would be a safe) or the provision of circuit integrity

measures to keep electrical cables operational during an accidental fire.

4.6.1.4 Regulations (sh)

The most important goal of PFP is identical to that of all fire protection: life safety. This is

mainly accomplished by maintaining structural integrity for a time during the fire, and limiting

the spread of fire and the effects thereof (e.g., heat and smoke). Property protection and

continuity of operations are usually secondary objectives in codes. Exceptions include nuclear

facilities and marine applications, as evacuation may be more complex or impossible. Nuclear

facilities, both buildings and ships, must also ensure the nuclear reactor does not experience a

nuclear meltdown. In this case, fixing the reactor may be more important than evacuation for key

safety personnel.

Examples of testing that underlies certification listing:



• Europe: BS EN 1364

• Netherlands: NEN 6068

• Germany: DIN 4102

• United Kingdom: BS 476

• Canada: ULC-S101

•

United States: ASTM E119

Each of these test procedures have very similar fire endurance regimes and heat transfer

limitations. Differences include the hose-stream tests, which are unique to Canada and the

United States, whereas Germany includes a very rigorous impact test during the fire for firewalls.

Germany is unique in including heat induced expansion and collapse of ferrous cable trays into

account for firestops, resulting in the favouring of firestop mortars, which tend to hold the

penetrating cable tray in place, whereas "softseals", typically made of rockwool and elastomeric

toppings, have been demonstrated in testing by Otto-Graf_institut to be torn open and rendered

inoperable when the cable tray expands, pushes in and then collapses. Spin-offs from these basictests cover closures, firestops and more. Furnace operations, thermocoupling and reporting

requirements remain uniform within each country.

In exterior applications for the offshore and the petroleum sectors, the fire endurance testing uses

a higher temperature and faster heat rise, whereas in interior applications, such as office

buildings, factories and residential, the fire endurance is based upon experiences gained from

burning wood. The interior fire time/temperature curve is referred to as "ETK" or the "building

elements" curve, whereas the high temperature variety is called the hydrocarbon curve as it is

based on burning oil and gas products, which burn hotter and faster. The most severe, and most

rarely used, of all fire exposure tests is the British "jetfire" test, which has been used to someextent in the UK and Norway but is not typically found in common regulations.

Typically, during the construction of buildings, fire protective systems must conform to the

requirements of building code that was in effect on the day that the building permit was applied

for. Enforcement for compliance with building codes is typically the responsibility of municipal

building departments. Once construction is complete, the building must maintain its design basis

by remaining in compliance with the current fire code, which is enforced by the fire prevention

officers of the municipal fire department. An up to date fire protection plan, containing a

complete inventory and maintenance details of all fire protection components, including

firestops, fireproofing, fire sprinklers, fire detectors, fire alarm systems, fire extinguishers, etc.are typical requirements for demonstration of compliance with applicable laws and regulations.

In order to know whether or not one's building is in compliance with fire safety regulations, it is

helpful to know what systems one has in place and what their installation and maintenance are

based upon.



Changes to fire protection systems or items affecting the structural or fire-integrity or use

(occupancy) of a building is subject to regulatory scrutiny. A contemplated change to a facility

requires a building permit, or, if the change is very minor, a review by the local fire prevention

officer. Such reviews by the Authority Having Jurisdiction (AHJ) also help to prevent potential

problems that may not be apparent to a building owner or contractors. Large and very common

deficiencies in existing buildings include the disabling of fire door closers through propping the

doors open and running rugs through them and perforating fire-resistance rated walls and floors

without proper firestopping.

"Old" versus "new"

Generally, one differentiates between "old" and "new" barrier systems. "Old" systems have been

tested and verified by governmental authorities including DIBt [2], the British Standards Institute

(BSI) and the National Research Council's Institute for Research in Construction [3]. These

organisations each publish in codes and standards, wall and floor assembly details that can be

used with generic, standardised components, to achieve quantified fire-resistance ratings.

Architects routinely refer to these details in drawings to enable contractors to build passive fire

protection barriers of certain ratings. The "old" systems are sometimes added to, through testing

performed in governmental laboratories such as those maintained by Canada's Institute for

Research in Construction, which then publishes the results in Canada's National Building Code

(NBC). Germany [4] and the UK, by comparison, publish their "old" systems in respective

standards, DIN4102 Part 4 (Germany) and BS476 (United Kingdom). "New" systems are

typically based on certification listings, whereby the installed configuration must comply with

the tolerances set out in the certification listing. The United Kingdom is an exception to this,

whereby certification, although not testing, is optional.

Countries where certification is optional

Fire tests in the UK are reported in the form of test results, but contrary to North America and

Germany, building authorities do not require written proof that the materials that have been

installed on site are actually identical to the materials and products that were used in the test. The

test report is also often interpreted by engineers, as the test results are not communicated in the

form of uniformly structured listings. In the UK, and other countries which do not require

certification, the proof that the manufacturer has not substituted other materials apart from those

used in the original testing is based on trust in the ethics or the culpability of the manufacturer.While in North America and in Germany, product certification is the key to the success and legal

defensibility of passive fire protection barriers, alternate quality control certifications of specific

installation companies and their work is available, though not a legislative or regulatory

requirement. Still, the question of how one can be sure, apart from faith in the vendor, that what

was tested is identical to that which has been bought and installed is a matter of personal

judgment. The most highly publicised example of PFP systems which were not subject of



certification and were declared inoperable by the Authority Having Jurisdiction is the Thermo-Lag scandal, which was brought to light by whistleblower Gerald W. Brown, who notified the

Nuclear Regulatory Commission of the inadequacy of fire testing for circuit integrity measures

in use in licensed nuclear power plants. This led to a congressional enquiry, significant press

coverage and a large amount of remedial work on the part of the industry to mitigate the

problem. There is no known case a similar instance for PFP systems which were under the

follow-up regime of organisations holding national accreditation for product certification, such

as DIBt or Underwriters Laboratories.

4.6.2 Active fire protection (h)

Active fire protection (AFP) is an integral part of fire protection. AFP is characterised by items

and/or systems, which require a certain amount of motion and response in order to work,

contrary to passive fire protection.

4.6.2.1 Categories of Active Fire Protection (sh)

Fire suppression

Fire can be controlled or extinguished, either manually (firefighting) or automatically. Manual

includes the use of a fire extinguisher or a Standpipe system. Automatic means can include a fire

sprinkler system, a gaseous clean agent, or firefighting foam system. Automatic suppression

systems would usually be found in large commercial kitchens or other high-risk area.

Sprinkler systems

Fire sprinkler systems are installed in all types of buildings, commercial and residential. They are

usually located at ceiling level and are connected to a reliable water source, most commonly city

water. A typical sprinkler system operates when heat at the site of a fire causes a glass

component in the sprinkler head to fail, thereby releasing the water from the sprinkler head. This

means that only the sprinkler head at the fire location operates - not all the sprinklers on a floor

or in a building. (This is a common misconception which stems from action movie scenes).

Sprinkler systems help to reduce the growth of a fire, thereby increasing life safety and limiting

structural damage.

Fire detection

Fire is detected either by locating the smoke, flame or heat, and an alarm is sounded to enable

emergency evacuation as well as to dispatch the local fire department. An introduction to fire

detection and suppression can be found here. Where a detection system is activated, it can be

programmed to carry out other actions. These include de-energising magnetic hold open devices

on Fire doors and opening servo-actuated vents in stairways.



Hypoxic air fire prevention

Fire can be prevented by hypoxic air. Hypoxic air fire prevention systems, also known as oxygen

reduction systems are new automatic fire prevention systems that reduce permanently the oxygen

concentration inside the protected volumes so that ignition or fire spreading cannot occur. Unlike

traditional fire suppression systems that usually extinguish fire after it is detected, hypoxic air is

able to prevent fires.

4.6.2.2 Construction and maintenance (sh)

All AFP systems are required to be installed and maintained in accordance with strict guidelines

in order to maintain compliance with the local building code and the fire code. An example

treatise on code compliance in Miami Dade County can be seen here. Code authorities can

encourage compliance through open communications, such as an invitation for code questions or

an invitation to participate or an explanation of the code development process AFP works

alongside modern architectural designs and construction materials and fire safety education to

prevent, retard, and suppress structural fires.

4.7 site planning and fire brigade access (mh)

DEFINITIONSFIRE APPARATUS ACCESS ROAD. A road that provides fire apparatus access from a fire

station to a facility, building or portion thereof. This is a general term inclusive of all other terms

such as fire lane, public street, private street, parking lot lane and access roadway.

FIRE LANE. A road or other passageway developed to allow the passage of fire apparatus. A

fire lane is not necessarily intended for vehicular traffic other than fire apparatus.

4.7.1 FIRE APPARATUS ACCESS ROADS (h)

4.7.1.1 Where required (sh)

Fire apparatus access roads shall be provided and maintained in accordance.

Buildings and facilities

Approved fire apparatus access roads shall be provided for every facility, building or portion of a

building hereafter constructed or moved into or within the jurisdiction. The fire apparatus access

road shall comply with the requirements of this section and shall extend to within 150 feet (45



720 mm) of all portions of the facility and all portions of the exterior walls of the first story of

the building as measured by an approved route around the exterior of the building or facility.

Exception: The fire code official is authorized to increase the dimension of 150 feet (45 720

mm) where:

1. The building is equipped throughout with an approved automatic sprinkler system installed.

2. Fire apparatus access roads cannot be installed because of location on property, topography,

waterways, non‐negotiable grades or other similar conditions, and an approved alternative means

of fire protection is provided.

3. There are not more than two Group R ‐3 or GroupU occupancies.

Additional access

The fire code official is authorized to require more than one fire apparatus access road based on

the potential for impairment of a single road by vehicle congestion, condition of terrain, climatic

conditions or other factors that could limit access.

High piled storage

Fire department vehicle access to buildings used for high‐ piled combustible storage shall comply

with the applicable provisions.

4.7.1.2 Specifications

Fire apparatus access roads shall be installed and arranged in accordance.

.

Dimensions

Fire apparatus access roads shall have an unobstructed width of not less than 20 feet (6096 mm),

except for approved security gates, and an unobstructed vertical clearance of not less than 13 feet

6 inches (4115 mm).

Authority

The fire code official shall have the authority to require an increase in the minimum access

widths where they are inadequate for fire or rescue operations.

Surface

Fire apparatus access roads shall be designed and maintained to support the imposed loads of fire

apparatus and shall be surfaced so as to provide all‐weather driving capabilities.



4. Gate components shall be maintained in an operative condition at all times and replaced or

repaired when defective.

5. Electric gates shall be equipped with a means of opening the gate by fire department personnel

for emergency access. Emergency opening devices shall be approved by the fire code official.

6. Manual opening gates shall not be locked with a padlock or chain and padlock unless they are

capable of being opened by means of forcible entry tools.

7. Locking device specifications shall be submitted for approval by the fire code official.

4.8 Roof covering – control of fire spread (mh)

A roof is the covering on the uppermost part of a building. A roof protects the building and its

contents from the effects of weather and the invasion of animals. Structures that require roofs

range from a letter box to a cathedral or stadium, dwellings being the most numerous.

In most countries a roof protects primarily against rain. In Persia the citizens used their roofs for

milling wheat, farming, gardens and extra space. Depending upon the nature of the building, the

roof may also protect against heat, sunlight, cold, snow and wind. Other types of structure, for

example, a garden conservatory, might use roofing that protects against cold, wind and rain but



admits light. A verandah may be roofed with material that protects against sunlight but admits

the other elements.

The characteristics of a roof are dependent upon the purpose of the building that it covers, the

available roofing materials and the local traditions of construction and wider concepts of

architectural design and practice and may also be governed by local or national legislation.

4.8.1 Design elements (h)

The elements in the design of a roof are:

• the material

• the construction

• the durability

The material of a roof may range from banana leaves, wheaten straw or seagrass to lamininatedglass, copper , aluminium sheeting and precast concrete. In many parts of the world ceramic tiles

have been the predominant roofing material for centuries.

The construction of a roof is determined by its method of support and how the underneath space

is bridged and whether or not the roof is pitched . The pitch is the angle at which the roof rises

from its lowest to highest point. Most US domestic architecture, except in very dry regions, has

roofs that are sloped, or pitched . Although modern construction elements such as drainpipes may

remove the need for pitch, roofs are pitched for reasons of tradition and aesthetics. So the pitch is

partly dependent upon stylistic factors, and partially to do with practicalities.

Some types of roofing, for example thatch, require a steep pitch in order to be waterproof and

durable. Other types of roofing, for example pantiles, are unstable on a steeply pitched roof but

provide excellent weather protection at a relatively low angle. In regions where there is little

rain, an almost flat roof with a slight run-off provides adequate protection against an occasional

downpour. Drainpipes also remove the need for a sloping roof.

The durability of a roof is a matter of concern because the roof is often the least accessible part

of a building for purposes of repair and renewal, while its damage or destruction can have

serious effects.

4.8.2 Form of a roof (h)

The shape of roofs differs greatly from region to region. The main factors which influence the

shape of roofs are the climate and the materials available for roof structure and the outer

covering.



A typical pitched roof

The basic shapes of roofs are flat, skillion, gabled, hipped, arched and domed. There are many

variations on these types. Roofs constructed of flat sections that are sloped are referred to as

pitched roofs (generally if the angle exceeds 10 degrees).[1] Pitched roofs, including gabled,

hipped and skillion roofs, make up the greatest number of domestic roofs. Some roofs followorganic shapes, either by architectural design or because a flexible material such as thatch has

been used in the construction.

Parts of a roof

There are two parts to a roof, its supporting structure and its outer skin, or uppermost

weatherproof layer. In a minority of buildings, the outer layer is also a self-supporting structure.

The roof structure is generally supported upon walls, although some building styles, for example,

geodesic and A-frame, blur the distinction between wall and roof.

4.8.3 Support (h)

The roof of a library in Sweden.

The supporting structure of a roof usually comprises beams that are long and of strong, fairly

rigid material such as timber, and since the mid-19th century, cast iron or steel. In countries that



faster, it does not allow the roof sheathing to be inspected and water damage, often associated

with worn shingles, to be repaired. Having multiple layers of old shingles under a new layer

causes roofing nails to be located further from the sheathing, weakening their hold. The greatest

concern with this method is that the weight of the extra material could exceed the dead load

capacity of the roof structure and cause collapse.

Slate is an ideal, and durable material, while in the Swiss Alps roofs are made from huge slabs of

stone, several inches thick. The slate roof is often considered the best type of roofing. A slate

roof may last 75 to 150 years, and even longer. However, slate roofs are often expensive to

install – in the USA, for example, a slate roof may have the same cost as the rest of the house.

Often, the first part of a slate roof to fail is the fixing nails; they corrode, allowing the slates to

slip. In the UK, this condition is known as "nail sickness". Because of this problem, fixing nails

made of stainless steel or copper are recommended, and even these must be protected from the

weather.

Asbestos, usually in bonded corrugated panels, has been used widely in the 20th century as an

inexpensive, non-flammable roofing material with excellent insulating properties. Health and

legal issues involved in the mining and handling of asbestos products means that it is no longer

used as a new roofing material. However, many asbestos roofs continue to exist, particularly in

South America and Asia.

Roofs made of cut turf (modern ones known as Green roofs, traditional ones as sod roofs) have

good insulating properties and are increasingly encouraged as a way of "greening" the Earth.

Adobe roofs are roofs of clay, mixed with binding material such as straw or animal hair, and

plastered on lathes to form a flat or gently sloped roof, usually in areas of low rainfall.

In areas where clay is plentiful, roofs of baked tiles have been the major form of roof. The

casting and firing of roof tiles is an industry that is often associated with brickworks. While the

shape and colour of tiles was once regionally distinctive, now tiles of many shapes and colours

are produced commercially, to suit the taste and pocketbook of the purchaser.

Sheet metal in the form of copper and lead has also been used for many hundreds of years. Both

are expensive but durable, the vast copper roof of Chartres Cathedral, oxidised to a pale green

colour, having been in place for hundreds of years. Lead, which is sometimes used for church

roofs, was most commonly used as flashing in valleys and around chimneys on domestic roofs, particularly those of slate. Copper was used for the same purpose.

In the 19th century, iron, electroplated with zinc to improve its resistance to rust, became a light-

weight, easily-transported, waterproofing material. Its low cost and easy application made it the

most accessible commercial roofing, world wide. Since then, many types of metal roofing have

been developed. Steel shingle or standing-seam roofs last about 50 years or more depending on



both the method of installation and the moisture barrier (underlayment) used and are between the

cost of shingle roofs and slate roofs. In the 20th century a large number of roofing materials were

developed, including roofs based on bitumen (already used in previous centuries), on rubber and

on a range of synthetics such as thermoplastic and on fibreglass.

4.8.5 Functions of a roof (h)

4.8.5.1 Insulation (sh)

Concrete tiles being installed on a roof top in Haikou City, Hainan, China.

Because the purpose of a roof is to protect people and their possessions from climatic elements,

the insulating properties of a roof are a consideration in its structure and the choice of roofing

material.

Some roofing materials, particularly those of natural fibrous material, such as thatch, have

excellent insulating properties. For those that do not, extra insulation is often installed under the

outer layer. In developed countries, the majority of dwellings have a ceiling installed under the

structural members of the roof. The purpose of a ceiling is to insulate against heat and cold,

noise, dirt and often from the droppings and lice of birds who frequently choose roofs as nesting

places.

Concrete tiles can be used as insulation. When installed leaving a space between the tiles and the

roof surface, it can reduce heating caused by the sun.

Forms of insulation are felt or plastic sheeting, sometimes with a reflective surface, installed

directly below the tiles or other material; synthetic foam batting laid above the ceiling andrecycled paper products and other such materials that can be inserted or sprayed into roof

cavities. So called Cool roofs are becoming increasingly popular, and in some cases are

mandated by local codes. Cool roofs are defined as roofs with both high reflectivity and high

thermal emittance.



Poorly insulated and ventilated roofing can suffer from problems such as the formation of ice

dams around the overhanging eaves in cold weather, causing water from melted snow on upper

parts of the roof to penetrate the roofing material. Ice dams occur when heat escapes through the

uppermost part of the roof, and the snow at those points melts, refreezing as it drips along the

shingles, and collecting in the form of ice at the lower points. This can result in structural

damage from stress, including the destruction of gutter and drainage systems.

4.8.5.2 Drainage (sh)

The primary job of most roofs is to keep out water. The large area of a roof repels a lot of water,

which must be directed in some suitable way, so that it does not cause damage or inconvenience.

Flat roof of adobe dwellings generally have a very slight slope. In a Middle Eastern country,

where the roof may be used for recreation, it is often walled, and drainage holes must be

provided to stop water from pooling and seeping through the porous roofing material.

Similar problems, although on a very much larger scale, confront the builders of modern

commercial properties which often have flat roofs. Because of the very large nature of such

roofs, it is essential that the outer skin is of a highly impermeable material. Most industrial and

commercial structures have conventional roofs of low pitch.

In general, the pitch of the roof is proportional to the amount of precipitation. Houses in areas of

low rainfall frequently have roofs of low pitch while those in areas of high rainfall and snow,

have steep roofs. The longhouses of Papua New Guinea, for example, being roof-dominated

architecture, the high roofs sweeping almost to the ground. The high steeply-pitched roofs of

Germany and Holland are typical in regions of snowfall. In parts of North America such as

Buffalo, USA or Montreal, Canada, there is a required minimum slope of 6 inches in 12 inches, a

pitch of 30 degrees.

There are regional building styles which contradict this trend, the stone roofs of the Alpine

chalets being usually of gentler incline. These buildings tend to accumulate a large amount of

snow on them, which is seen as a factor in their insulation. The pitch of the roof is in part

determined by the roofing material available, a pitch of 3/12 or greater slope generally being

covered with asphalt shingles, wood shake, corrugated steel, slate or tile.

The water repelled by the roof during a rainstorm is potentially damaging to the building that the

roof protects. If it runs down the walls, it may seep into the mortar or through panels. If it lies

around the foundations it may cause seepage to the interior, rising damp or dry rot. For this

reason most buildings have a system in place to protect the walls of a building from most of the

roof water. Overhanging eaves are commonly employed for this purpose. Most modern roofs and

many old ones have systems of valleys, gutters, waterspouts, waterheads and drainpipes to



remove the water from the vicinity of the building. In many parts of the world, roofwater is

collected and stored for domestic use.

Areas prone to heavy snow benefit from a metal roof because their smooth surfaces shed the

weight of snow more easily and resist the force of wind better than a wood shingle or a concrete

tile roof.

• Insulation, drainage and solar roofing

•

• Snow on the roofs of houses in Poland.

•

• The flat roofs of the Middle East, Israel.

•

• Steeply pitched, gabled roofs in Northern Europe.

•

• The overhanging eaves of China.

•



4.8.6 Solar roofs (h)

Newer systems include solar shingles which generate electricity as well as cover the roof. There

are also solar systems available that generate hot water or hot air and which can also act as a roof

covering. More complex systems may carry out all of these functions: generate electricity,

recover thermal energy, and also act as a roof covering.

Solar systems can be integrated with roofs by:

• integration in the covering of pitched roofs, e.g. solar shingles.

• mounting on an existing roof, e.g. solar panel on a tile roof.

• integration in a flat roof membrane using heat welding, e.g. PVC.

• mounting on a flat roof with a construction and additional weight to prevent uplift from

wind.

•

Roof shapes

•

• Flat roof, Western Australia.

•

• Mansard roof on a county jail, Mount Gilead, Ohio.

•

• Temple roof Chang Mai, Thailand with a decorated gable end and ceramic tile covering.



•

• Conical Chinese roof at the Nanhai Academy in Taipei.

•

• Church of Our Saviour, Copenhagen, Denmark. Complex hip roof with cross gable and

eight valleys and a slight kick near the bottom, roofed in tiles and copper with a box

gutter. Roof viewed from the steeple.

•

Swedish Sateri roof form.

4.9 Heat sensitive detectors (mh)

Mechanical heat detector, both rate of rise and fixed temperature operation

A heat detector is a fire alarm device designed to respond when the convected thermal energy of

a fire increases the temperature of a heat sensitive element. The thermal mass and conductivity of



the element regulate the rate flow of heat into the element. All heat detectors have this thermal

lag. Heat detectors have two main classifications of operation, "rate-of-rise" and "fixed

temperature."

4.9.1 Fixed temperature heat detectors (h)

This is the most common type of heat detector. Fixed temperature detectors operate when the

heat sensitive eutectic alloy reaches the eutectic point changing state from a solid to a liquid.

Thermal lag delays the accumulation of heat at the sensitive element so that a fixed-temperature

device will reach its operating temperature sometime after the surrounding air temperature

exceeds that temperature. The most common fixed temperature point for electrically connected

heat detectors is 136.4°F (58°C). Technological developments have enabled the perfection of

detectors that activate at a temperature of 117°F (47°C), increasing the available reaction time

and margin of safety. This type of technology has been available for decades without the use of

batteries or electricity as shown in the picture.

4.9.1.1 Rate-of-rise heat detectors (sh)

Rate-of-Rise (ROR) heat detectors operate on a rapid rise in element temperature of 12° to 15°F

(6.7° to 8.3°C) increase per minute, irrespective of the starting temperature. This type of heat

detector can operate at a lower temperature fire condition than would be possible if the threshold

were fixed. It has two heat-sensitive thermocouples or thermistors. One thermocouple monitors

heat transferred by convection or radiation. The other responds to ambient temperature. Detector

responds when first’s temperature increases relative to the other.

Rate of rise detectors may not respond to low energy release rates of slowly developing fires. To

detect slowly developing fires combination detectors add a fixed temperature element that will

ultimately respond when the fixed temperature element reaches the design threshold.

4.9.1.2 Heat detector selection (sh)

Heat detectors commonly have a label on them that says "Not a life safety device". That is

because heat detectors are not meant to replace smoke detectors in the bedrooms or in the

hallway outside of the bedrooms. A heat detector will nonetheless notify of a fire in a kitchen or

utility area (i.e., laundry room, garage, or attic), where smoke detectors should not be installed.

This will allow extra time to evacuate the building or to put out the fire if possible.

Mechanical heat detectors are independent fire warning stations that - unlike smoke detectors -

can be installed in any area of a home. Portability, ease of installation, and excellent performance

and reliability make this a good choice for residential fire protection when combined with the



required smoke detectors. Because the detectors are not interconnected, heat activation identifies

the location of the fire, facilitating evacuation from the home.

Each type of heat detector has its advantages, and it cannot be said that one type of heat detector

should always be used instead of another. If you were to place a rate-of-rise heat detector above a

large, closed oven, then every time the door is opened a nuisance alarm could be generated due

to the sudden heat transient. In this circumstance the fixed threshold detector would probably be

best. If a room filled with highly combustible materials is protected with a fixed heat detector

then a fast-flaming fire could exceed the alarm threshold due to thermal lag. In that case the rate-

of-rise heat detector may be preferred.

4.10 smoke detectors (mh)

A smoke detector is a device that detects smoke, typically as an indicator of fire. Commercial,

industrial, and mass residential devices issue a signal to a fire alarm system, while household

detectors, known as smoke alarms, generally issue a local audible or visual alarm from the

detector itself.

Smoke detectors are typically housed in a disk-shaped plastic enclosure about 150 millimetres

(6 in) in diameter and 25 millimetres (1 in) thick, but the shape can vary by manufacturer or

product line. Most smoke detectors work either by optical detection (photoelectric) or by

physical process (ionization), while others use both detection methods to increase sensitivity to

smoke. Sensitive alarms can be used to detect, and thus deter, smoking in areas where it is

banned such as toilets and schools. Smoke detectors in large commercial, industrial, andresidential buildings are usually powered by a central fire alarm system, which is powered by the

building power with a battery backup. However, in many single family detached and smaller

multiple family housings, a smoke alarm is often powered only by a single disposable battery.

In the United States, the National Fire Protection Association estimates that nearly two-thirds of

deaths from home fires occur in properties without working smoke alarms/detectors.



4.10.1 Design (h)

4.10.1.1 Optical (sh)

Optical Smoke Detector with the cover removed.

Optical Smoke Detector

1: Optical chamber

2: Cover

3: Case moulding

4: Photodiode (detector)

5: Infrared LED



Inside a basic ionization smoke detector. The black, round structure at the right is the ionization

chamber. The white, round structure at the upper left is the piezoelectric buzzer that produces the

alarm sound.

An optical detector is a light sensor. When used as a smoke detector, it includes a light source

(incandescent bulb or infrared LED-Light-Emitting Diode), a lens to collimate the light into a

beam, and a photodiode or other photoelectric sensor at an angle to the beam as a light detector.

In the absence of smoke, the light passes in front of the detector in a straight line. When smoke

enters the optical chamber across the path of the light beam, some light is scattered by the smoke

particles, directing it at the sensor and thus triggering the alarm.

Also seen in large rooms, such as a gymnasium or an auditorium, are devices that detect a

projected beam. A wall-mounted unit sends out a beam, which is either received by a separate

monitoring device or reflected back via a mirror. When the beam becomes less visible to the

"eye" of the sensor, it sends an alarm signal to the fire alarm control panel.

According to the National Fire Protection Association (NFPA), "photoelectric smoke detection is

generally more responsive to fires that begin with a long period of smoldering (called smoldering

fires)." Also, studies by Texas A&M and the NFPA cited by the City of Palo Alto California

state, "Photoelectric alarms react slower to rapidly growing fires than ionization alarms, but

laboratory and field tests have shown that photoelectric smoke alarms provide adequate warning

for all types of fires and have been shown to be far less likely to be deactivated by occupants."

Although optical alarms are highly effective at detecting smouldering fires and do provide

adequate protection from flaming fires, some fire safety experts and the National Fire ProtectionAssociation recommend installing what are called combination alarms, which are alarms that

either detect both heat and smoke, or use both the ionization and photoelectric/optical processes.

Also some combination alarms may include a carbon monoxide detection capability.

Combination ionization/photoelectric smoke alarms are controversial. The World Fire Safety

Foundation (WFSF), the International Association of Fire Fighters (IAFF), the Australasian Fire

and Emergency Service Authorities Council (AFAC), the Fire Protection Association of

Australia and a growing number of fire departments, consumer and fire safety experts around the

world do not recommend them. The official positions of the WFSF, the IAFF and AFAC state,

"Ionization smoke alarms may not operate in time to alert occupants early enough to escape fromsmoldering fires." However, stand-alone photoelectric smoke alarms are proven to provide

adequate egress time in both the smoldering and flaming stages of fire.

Not all optical or photoelectric detection methods are the same. The type and sensitivity of the

photodiode or optical sensor, and type of smoke chamber differ between manufacturers.



An optical beam smoke detector works for large open spaces.

4.10.1.2 Ionization (sh)

An Americium container from a smoke detector.

An ionization smoke detector uses a radioisotope such as americium-241 to produce ionization in

air; a difference due to smoke is detected and an alarm is generated. Ionization detectors are

more sensitive to the flaming stage of fires than optical detectors, while optical detectors are

more sensitive to fires in the early smouldering stage.

The radioactive isotope americium-241 in the smoke detector emits ionizing radiation in the

form of alpha particles into an ionization chamber (which is open to the air) and a sealed

reference chamber. The air molecules in the chamber become ionized and these ions allow the

passage of a small electric current between charged electrodes placed in the chamber. If any

smoke particles pass into the chamber the ions will attach to the particles and so will be less able

to carry the current. An electronic circuit detects the current drop, and sounds the alarm. The

reference chamber cancels effects due to air pressure, temperature, or the aging of the source.

Other parts of the circuitry monitor the battery (where used) and sound an intermittent warning

when the battery nears exhaustion. A self-test circuit simulates an imbalance in the ionization

chamber and verifies the function of power supply, electronics, and alarm device. The standby

power draw of an ionization smoke detector is so low that a small battery can provide power for

months or years, making the unit independent of AC power supply or external wiring; however,

batteries require regular test and replacement.

An ionization type smoke detector is generally cheaper to manufacture than an optical smoke

detector; however, it is sometimes rejected because it is more prone to false (nuisance) alarms

than photoelectric smoke detectors. It can detect particles of smoke that are too small to be

visible.

Americium-241, an alpha emitter, has a half-life of 432 years. Alpha radiation, as opposed to

beta and gamma, is used for two additional reasons: Alpha particles have high ionization, so



sufficient air particles will be ionized for the current to exist, and they have low penetrative

power, meaning they will be stopped by the plastic of the smoke detector or the air. About one

percent of the emitted radioactive energy of 241Am is gamma radiation. The amount of elemental

americium-241 is small enough to be exempt from the regulations applied to larger sources. It

includes about 37 kBq or 1 µCi of radioactive element americium-241 (241Am), corresponding to

about 0.3 µg of the isotope. This provides sufficient ion current to detect smoke, while producing

a very low level of radiation outside the device.

The americium-241 in ionizing smoke detectors poses a potential environmental hazard.

Disposal regulations and recommendations for smoke detectors vary from region to region.

Some European countries have banned the use of domestic ionic smoke alarms.

4.10.1.3 Radiation data (sh)

Type Energy Percentage

Alpha 5485 keV 84.5%

Alpha 5443 keV 13.0%

Gamma 59.5 keV 35.9%

Gamma 26.3 keV 2.4%

Gamma 13.9 keV 42%

Specific activity is 3.5 Ci/g.

4.10.1.4 Air-sampling (sh)

An air-sampling smoke detector is capable of detecting microscopic particles of smoke. Most air-

sampling detectors are aspirating smoke detectors, which work by actively drawing air through a

network of small-bore pipes laid out above or below a ceiling in parallel runs covering a

protected area. Small holes drilled into each pipe form a matrix of holes (sampling points),

providing an even distribution across the pipe network. Air samples are drawn past a sensitiveoptical device, often a solid-state laser, tuned to detect the extremely small particles of

combustion. Air-sampling detectors may be used to trigger an automatic fire response, such as a

gaseous fire suppression system, in high-value or mission-critical areas, such as archives or

computer server rooms.



Most air-sampling smoke detection systems are capable of a higher sensitivity than spot type

smoke detectors and provide multiple levels of alarm threshold, such as Alert, Action, Fire 1 and

Fire 2. Thresholds may be set at levels across a wide range of smoke levels. This provides earlier

notification of a developing fire than spot type smoke detection, allowing manual intervention or

activation of automatic suppression systems before a fire has developed beyond the smoldering

stage, thereby increasing the time available for evacuation and minimizing fire damage.

Carbon monoxide and carbon dioxide detection

Some smoke alarms use a carbon dioxide sensor or carbon monoxide sensor to detect extremely

dangerous products of combustion. However, gas sensors able to warn of poisonous levels of

those gases in the absence of a fire have sensitivities based on the uptake of carbon monoxide by

haemoglobin, and are not generally sensitive or fast enough to be used as fire detectors.

Performance differences

Photoelectric smoke detectors respond faster (typically 30 minutes or more) to fire in its early,

smouldering stage (before it breaks into flame). The smoke from the smouldering stage of a fire

is typically made up of large combustion particles — between 0.3 and 10.0 µm. Ionization

smoke detectors respond faster (typically 30–60 seconds) in the flaming stage of a fire. The

smoke from the flaming stage of a fire is typically made up of microscopic combustion particles

— between 0.01 and 0.3 µm. Also, ionization detectors are weaker in high air-flow

environments, and because of this, the photoelectric smoke detector is more reliable for detecting

smoke in both the smoldering and flaming stages of a fire.

In June, 2006 the Australasian Fire & Emergency Service Authorities Council, the peak

representative body for all Australian and New Zealand Fire Departments published an official

report, 'Position on Smoke Alarms in Residential Accommodation'. Clause 3.0 states, "Ionization

smoke alarms may not operate in time to alert occupants early enough to escape from

smouldering fires."

In August, 2008 the International Association of Fire Fighters (IAFF-300,000+ members

throughout the USA and Canada) passed a Resolution recommending the use of photoelectric

smoke alarms. The IAFF states that changing to photoelectric alarms, "Will drastically reduce

the loss of life among citizens and fire fighters."

In June, 2010 the City of Albany, California enacted photoelectric-only legislation after a

unanimous decision by the Albany City Council. This was a catalyst for several other Californian

and Ohioan cities to enact legislation requiring photoelectric smoke detectors.



In May, 2011 the Fire Protection Association of Australia's (FPAA) official position on smoke

alarms states, "Fire Prevention Association Australia considers that all residential buildings

should be fitted with photoelectric smoke alarms...".

In November, 2011 the Northern Territory enacted Australia's first residential photoelectric

legislation mandating the use of photoelectric smoke alarms in all new Northern Territory

homes.

In December, 2011 the Volunteer Fire Fighter's Association of Australia published a World Fire

Safety Foundation report, 'Ionization Smoke Alarms are DEADLY", citing research outlining

substantial performance differences between ionization and photoelectric technology.

In June, 2013 in an Australian Parliamentary speech, the question was asked, "Are ionization

smoke alarms defective?" This was further to the Australian Government's scientific testing

agency (the Commonwealth Scientific and Industrial Research Organization - CSIRO) data

revealing serious performance problems with ionization technology in the early, smoldering

stage of fire, a rise in litigation involving ionization smoke alarms, and increasing legislation

mandating the installation of photoelectric smoke alarms. The speech cited a May 2013, World

Fire Safety Foundation report published in the Australian Volunteer Fire Fighter Association's

magazine titled, 'Can Australian and U.S. Smoke Alarm Standards be Trusted?' The speech

concluded with a request for one of the world's largest ionization smoke alarm manufacturers

and the CSIRO to disclose the level of visible smoke the manufacturers' ionization smoke alarms

activate under CSIRO scientific testing.

According to fire tests conformant to EN 54, the CO2 cloud from open fire can usually bedetected before particulate.

Due to the varying levels of detection capabilities between detector types, manufacturers have

designed multi-criteria devices which cross-reference the separate signals to both rule out false

alarms and improve response times to real fires. Examples include Photo/heat, photo/CO, and

even CO/photo/heat/IR.

Obscuration is a unit of measurement that has become the standard definition of smoke detector

sensitivity. Obscuration is the effect that smoke has on reducing sensor visibility; higher

concentrations of smoke result in higher obscuration levels.

4.10.2 Typical smoke detector obscuration ratings (h)

Type of Detector Obscuration Level

Ionization 2.6–5.0% obs/m (0.8–1.5% obs/ft)



Photoelectric 6.5–13.0% obs/m (2–4% obs/ft)

Beam 3% obs/m (0.9% obs/ft)

Aspirating 0.005–20.5% obs/m (0.0015–6.25% obs/ft)

Laser 0.06–6.41% obs/m (0.02–2.0% obs/ft)

4.10.2.1 Commercial smoke detectors (sh)

An integrated locking mechanism for commercial building doors. Inside an enclosure are a

locking device, smoke detector and power supply.

Commercial smoke detectors are either conventional or analog addressable, and are wired up to

security monitoring systems or fire alarm control panels (FACP). These are the most common

type of detector, and usually cost a lot more than a household smoke alarms. They exist in most

commercial and industrial facilities, such as high rises, ships and trains. These detectors don't

need to have built in alarms, as alarm systems can be controlled by the connected FACP, which

will set off relevant alarms, and can also implement complex functions such as a staged

evacuation.

4.10.2.2 Conventional (sh)

The word "conventional" is slang used to distinguish the method used to communicate with the

control unit from that used by addressable detectors whose methods were unconventional at the

time of their introduction. So called “Conventional Detectors” cannot be individually identified

by the control unit and resemble an electrical switch in their information capacity. These

detectors are connected in parallel to the signaling path or (initiating device circuit) so that the

current flow is monitored to indicate a closure of the circuit path by any connected detector when



smoke or other similar environmental stimulus sufficiently influences any detector. The resulting

increase in current flow is interpreted and processed by the control unit as a confirmation of the

presence of smoke and a fire alarm signal is generated.

4.10.2.3 Addressable (sh)

An addressable Simplex smoke detector

This type of installation gives each detector on a system an individual number, or address. Thus,

addressable detectors allow an FACP, and therefore fire fighters, to know the exact location of

an alarm where the address is indicated on a diagram.

Analog addressable detectors provide information about the amount of smoke in their detection

area, so that the FACP can decide itself, if there is an alarm condition in that area (possibly

considering day/night time and the readings of surrounding areas). These are usually more

expensive than autonomous deciding detectors.

4.10.2.4 Single Station Smoke Alarms (sh)

The main function of a single station or "standalone" smoke alarm is to alert persons at risk.

Several methods are used and documented in industry specifications published by Underwriters

Laboratories Alerting methods include:

• Audible tones

o Usually around 3200 Hz due to component constraints (Audio advancements for

persons with hearing impairments have been made; see External links)

o

85 dBA at 10 feet

• Spoken voice alert

• Visual strobe lights

o 177 candela output

• Tactile stimulation, e.g., bed or pillow shaker (No standards exist as of 2008 for tactile

stimulation alarm devices.)



Some models have a hush or temporary silence feature that allows silencing without removing

the battery. This is especially useful in locations where false alarms can be relatively common

(e.g. due to "toast burning") or users could remove the battery permanently to avoid the

annoyance of false alarms, but removing the battery permanently is strongly discouraged.

While current technology is very effective at detecting smoke and fire conditions, the deaf and

hard of hearing community has raised concerns about the effectiveness of the alerting function in

awakening sleeping individuals in certain high-risk groups such as the elderly, those with hearing

loss and those who are intoxicated. Between 2005 and 2007, research sponsored by the United

States' National Fire Protection Association (NFPA) has focused on understanding the cause of a

higher number of deaths seen in such high-risk groups. Initial research into the effectiveness of

the various alerting methods is sparse. Research findings suggest that a low frequency (520 Hz)

square wave output is significantly more effective at awakening high risk individuals. Wireless

smoke and carbon monoxide detectors linked to alert mechanisms such as vibrating pillow pads

for the hearing impaired, strobes, and remote warning handsets are more effective at waking people with serious hearing loss than other alarms.

4.10.2.5 Batteries (sh)

Photoelectric smoke detector equipped with strobe light for the hearing impaired

Most residential smoke detectors run on 9-volt alkaline or carbon-zinc batteries. When these

batteries run down, the smoke detector becomes inactive. Most smoke detectors will signal a

low-battery condition. The alarm may chirp at intervals if the battery is low, though if there ismore than one unit within earshot, it can be hard to locate. It is common, however, for houses to

have smoke detectors with dead batteries. It is estimated, in the UK, that over 30% of smoke

alarms may have dead or removed batteries. As a result, public information campaigns have been

created to remind people to change smoke detector batteries regularly. In Australia, for example,

a public information campaign suggests that smoke alarm batteries should be replaced on April



Fools' Day every year. In regions using daylight saving time, campaigns may suggest that people

change their batteries when they change their clocks or on a birthday.

Some detectors are also being sold with a lithium battery that can run for about 7 to 10 years,

though this might actually make it less likely for people to change batteries, since their

replacement is needed so infrequently. By that time, the whole detector may need to be replaced.

Though relatively expensive, user-replaceable 9-volt lithium batteries are also available.

Common NiMH and NiCd rechargeable batteries have a high self-discharge rate, making them

unsuitable for use in smoke detectors. This is true even though they may provide much more

power than alkaline batteries if used soon after charging, such as in a portable stereo. Also, a

problem with rechargeable batteries is a rapid voltage drop at the end of their useful charge. This

is of concern in devices such as smoke detectors, since the battery may transition from "charged"

to "dead" so quickly that the low-battery warning period from the detector is either so brief as to

go unnoticed, or may not occur at all.

The NFPA, recommends that home-owners replace smoke detector batteries with a new battery

at least once per year, when it starts chirping (a signal that its charge is low), or when it fails a

test, which the NFPA recommends to be carried out at least once per month by pressing the

"test" button on the alarm.

4.10.2.6 Reliability (sh)

In 2004, NIST issued a comprehensive report that concludes, among other things, that "smoke

alarms of either the ionization type or the photoelectric type consistently provided time for

occupants to escape from most residential fires", and "consistent with prior findings, ionization

type alarms provided somewhat better response to flaming fires than photoelectric alarms (57 to

62 seconds faster response), and photoelectric alarms provided (often) considerably faster

response to smoldering fires than ionization type alarms (47 to 53 minutes faster response)".

The NFPA strongly recommends the replacement of home smoke alarms every 10 years. Smoke

alarms become less reliable with time, primarily due to aging of their electronic components,

making them susceptible to nuisance false alarms. In ionization type alarms, decay of the241

Am

radioactive source is a negligible factor, as its half-life is far greater than the expected useful life

of the alarm unit.

Regular cleaning can prevent false alarms caused by the build up of dust or other objects such as

flies, particularly on optical type alarms as they are more susceptible to these factors. A vacuum

cleaner can be used to clean ionization and optical detectors externally and internally. However,

on commercial ionisation detectors it is not recommended for a lay person to clean internally. To



reduce false alarms caused by cooking fumes, use an optical or 'toast proof' alarm near the

kitchen.

A jury in the United States District Court for the Northern District of New York decided in 2006

that First Alert and its parent company, BRK Brands, was liable for millions of dollars in

damages because the ionization smoke alarm in the Hackert's house was a defective design by its

nature, typically failing to detect the slow-burning fire and choking smoke that filled the home as

the family slept.

4.10.3 Installation and placement (h)

A 2007 U.S. guide to placing smoke detectors, suggesting that one be placed on every floor of a

building, and in each bedroom.

In the United States, most state and local laws regarding the required number and placement ofsmoke detectors are based upon standards established in NFPA 72, National Fire Alarm and

Signaling Code.

Laws governing the installation of smoke detectors vary depending on the locality. Homeowners

with questions or concerns regarding smoke detector placement may contact their local fire

marshal or building inspector for assistance. However, some rules and guidelines for existing



homes are relatively consistent throughout the developed world. For example, Canada and

Australia require a building to have a working smoke detector on every level. The United States

NFPA code cited in the previous paragraph requires smoke detectors on every habitable level

and within the vicinity of all bedrooms. Habitable levels include attics that are tall enough to

allow access.

In new construction, minimum requirements are typically more stringent. All smoke detectors

must be hooked directly to the electrical wiring, be interconnected and have a battery backup. In

addition, smoke detectors are required either inside or outside every bedroom, depending on

local codes. Smoke detectors on the outside will detect fires more quickly, assuming the fire does

not begin in the bedroom, but the sound of the alarm will be reduced and may not wake some

people. Some areas also require smoke detectors in stairways, main hallways and garages.

Wired units with a third "interconnect" wire allow a dozen or more detectors to be connected, so

that if one detects smoke, the alarms will sound on all the detectors in the network, improving

the chances that occupants will be alerted, even if they are behind closed doors or if the alarm is

triggered one or two floors from their location. Wired interconnection may only be practical for

use in new construction, especially if the wire needs to be routed in areas that are inaccessible

without cutting open walls and ceilings. As of the mid-2000s, development has begun on

wirelessly networking smoke alarms, using technologies such as ZigBee, which will allow

interconnected alarms to be easily retrofitted in a building without costly wire installations. Some

wireless systems using Wi-Safe technology will also detect smoke or carbon monoxide through

the detectors, which simultaneously alarm themselves with vibrating pads, strobes and remote

warning handsets. As these systems are wireless they can easily be transferred from one property

to another.

In the UK the placement of detectors are similar however the installation of smoke alarms in new

builds need to comply to the British Standards BS5839 pt6. BS 5839: Pt.6: 2004 recommends

that a new-build property consisting of no more than 3 floors (less than 200sqm per floor) should

be fitted with a Grade D, LD2 system. Building Regulations in England, Wales and Scotland

recommend that BS 5839: Pt.6 should be followed, but as a minimum a Grade D, LD3 system

should be installed. Building Regulations in Northern Ireland require a Grade D, LD2 system to

be installed, with smoke alarms fitted in the escape routes and the main living room and a heat

alarm in the kitchen, this standard also requires all detectors to have a main supply and a battery

back up.

4.10.3.1 EN54 European Standard for Smoke Detector (sh)

Fire detection products have the European Standard EN 54 Fire Detection and Fire Alarm

Systems that is a mandatory standard for every product that is going to be delivered and installed

in any country in the European Union (EU). EN 54 part 7 is the standard for smoke detectors.



European standard are developed to allow free movement of goods in the European Union

countries. EN 54 is widely recognized around the world. The EN 54 certification of each device

must be issued annually.

Coverage of Smoke Detector and Temperature detector with European Standard EN54 (sqm)

Superfice area(sqm)

Type of DetectorHeigh(m)

Roof Slope ≤20º Roof Slope >20º

Smax(sqm)Rmax

(m)

Smax

(sqm)Rmax(m)

SA ≤80 EN54-7 ≤12 80 6,6 80 8,2

SA >80

EN54-7 ≤6 60 5,7 90 8,7

6< h ≤ 12

80 6,6 110 9,6

SA ≤30

EN54-5 Clase A1 ≤7,5 30 4,4 30 5,7

EN54-5, Clase

A2,B,C,D,F,G≤ 6 30 4,4 30 5,7

SA >30

EN54-5 Clase A1 ≤7,5 20 3,5 40 6,5

EN54-5 ClaseA2,B,C,D,E,F,G ≤6 20 3,5 40 6,5

• EN54-7, Smoke detector.

• EN54-5, Temperature detector.

• SA = Superfice Area.

• Smax(sqm) = Maximum Superfice coverage.

• Rmax (m) = Maximum Radio.

information in "bold" is the standard coverage of the detector. Smoke detector coverage is

60sqm and temperature smoke detector is 20sqm. Height from ground is an important issue for a

correct protection. You can see "High" in the table for this information.

4.10.3.2 Australian and United States smoke alarm standards (sh)

In June, 2013 a World Fire Safety Foundation report titled, 'Can Australian and U.S. Smoke

Alarm Standards be Trusted?' was published in the official magazine of the Australian Volunteer



Fire Fighter's Association. The report brings into question the validity of testing criteria used by

American and Australian government agencies when undergoing scientific testing of ionization

smoke alarms in smoldering fires.

4.11 Automatic water system (mh)

A light drizzle in the morning – a short refreshing shower in the evening. Or do you need your

garden to water itself while you’re away on holiday? With GARDENA watering computers or

water timers you’ll be in total control wherever you are, whenever you want.

Water computers can be used for controlling mobile sprinklers, a Micro-Drip-System or a small

Sprinklersystem installation. Whereas Irrigation Control Systems are ideal for controlling larger

Sprinklersystem installations with several separate lines.

GARDENA Water Computers and Timers offer a modern attractive design and are easy-to-use.

No complicated programming is necessary – all models are simple to use. Depending on which

model you choose different watering programs with flexible watering times, cycles, or days, are

available.

If you plan to have larger Sprinklersystem installations with different, separate water lines,

GARDENA Irrigation Control Systems offer you many flexible solutions. No matter if

electricity is available or not – different garden situations can be taken into account accordingly.

Programming is easy and not complex at all.

In combination with a GARDENA Rain or Soil Moisture Sensor, you can fully automate the

watering process in accordance to raining conditions or the moisture of the ground.

4.12 Fire safety, fire & human behavior (mh)

Mission:

The Task Group on Human Behavior will develop guidance on accounting for human

behavior in engineered fire protection design. Topics to be considered include response to

cues, pre-movement activities, predicting egress time and the effects of hazardousconditions on human behavior.

Current Activity:

The SFPE Task Group is beginning the process of updating the SFPE Engineering Guide

to Human Behavior in Fire. It is anticipated that guidance will be incorporated into the



next edition of the guide on conducting tenability analyses. If you would like to

participate in this activity, please submit an application to join the task group toIf you

would like to participate in this activity, please submit an application form.

4.13 Means of escape, design and planning of escape halts and corridors to final exit (mh)

4.13.1 What is a Fire Exit? (h)

The Regulatory Reform (Fire Safety) Order (RRFSO) 2005, which came into force in October

2006, charges the responsible person(s) in control of non-domestic premises with the safety of

everyone, whether employed in or visiting the building. Under Article 14 of the RRFSO, this

duty of care includes ensuring that “routes to emergency exits from premises and the exits

themselves are kept clear at all times” (14: 1) and that these “emergency routes and exits must

lead as directly as possible to a place of safety” (14: 2: a). In other words, the entire escape route

up to and including the final exit from a building must remain unobstructed at all times, while the

distance people have to go to escape (the travel distance) must be as short as possible.

In terms of fire safety, the final exits on an escape route in a public building are known as fire

exits. They may or may not be located on the usual route of traffic when the premises are

operating under normal circumstances. The final exit doors should open easily, immediately

and, wherever practicable, “in the direction of escape”, i.e. outwards into a place of safety

outside the building. Sliding or revolving doors must not be used for exits specifically intended

as fire exits. The emergency routes and fire exits must be well lit and indicated by appropriate

signs, e.g. ‘Fire Exit – Keep Clear’. In locations that require illumination, emergency lighting ofadequate intensity must be provided in case the normal lighting fails, and illuminated signs used.

This is because, as noted in the HM Government publication “Fire Safety Risk Assessment:

Offices and Shops” (May 2006): “The primary purpose of emergency escape lighting is to

illuminate escape routes but it also illuminates other safety equipment”.

4.13.2 Places of Relative Safety (h)

It is often necessary to devise a temporary place of safety, such as when evacuating high

buildings. This may be defined as a place of comparative safety and includes any place that puts

an effective barrier (normally 30 minutes’ fire resistance) between the person escaping and thefire. Examples are as follows:

1. A storey exit into a protected stairway or the lobby of a lobby approach stairway;

2. A door in a compartment wall or separating wall leading to an alternative exit;

3. A door that leads directly to a protected stair or a final exit via a protected corridor.



A staircase that is enclosed throughout its height by a fire resisting structure and doors can

sometimes be considered a place of comparative safety. In these cases, the staircase can be

known as a ‘protected route’. However, the degree of protection that enables staircases to be

considered a place of comparative safety varies for differing building types, and is normally

defined in the relevant codes of practice.

4.13.3 Place of Ultimate Safety (h)

Ideally, this should be in the open air, where unrestricted dispersal away from the building can be

achieved. Escape routes should never discharge finally into enclosed areas or yards, unless the

dispersal area is large enough to permit all the occupants to proceed to a safe distance. (NB: a

safe distance equates to at least the height of the building, measured along the ground.) Total

dispersal in the open air therefore constitutes ultimate safety. When inspecting any building, it is

important always to follow the escape route to its ultimate place of safety. Plus, the final exits on

these escape routes (i.e. fire exits) must have sufficient capacity to ensure the swift and safe

evacuation of people from the building in an emergency situation.

4.13.4 What is the Total Width of Fire Exits Required? (h)

There are two main sources of guidance that should be consulted when considering the above

question for your premises: the Building Regulations and British Standards.

1) Building Regulations: the maximum number of persons approach

Current building regulations contain guidance on the widths of escape routes and exits for new-

build, non-domestic properties and the communal areas in purpose built blocks of flats in “The

Building Regulations 2010, Fire Safety, Approved Document B, Volume 2 – Buildings Other

Than Dwellinghouses, 2006 edition, incorporating 2007 and 2010 amendments”.

2) British Standards: the risk profile approach

The current BSI “Code of practice for fire safety in the design, management and use of

buildings” (BS 9999: 2008) takes a complementary approach to this calculation, based on two

main factors: occupancy characteristic and fire growth rate. Combining these two factors

creates the risk profile of a specific building. This means that, rather than the prescriptiveformula evident in earlier BSi publications on the matter, there is scope for a much more

interpretative approach, on a case by case basis, which takes into account the specific features of

an individual building. This is especially significant when considering the issue of escape routes

and fire exits in existing premises, particularly if they are of an historical or heritage nature.



The occupancy characteristic is principally determined according to whether the occupants are

familiar or unfamiliar with the building (i.e. the difference between emergency and panic exits)

and whether they are likely to be awake or asleep

4.13.5 The Process of Escape (h)

Having considered the factors that will influence escape, and having seen how these can be

related to the risk profile and / or occupancy levels of a specific building, it is important to look

at the stages in the process of escape and the maximum distances people can be expected to

travel.

Escape is generally considered in four distinct ‘Stages’ as follows

Stage 1 – escape from the room or area of fire origin

Stage 2 – escape from the compartment of origin via the circulation route to a protected stairway

or an adjoining compartment offering refuge

Stage 3 – escape from the floor of origin to the ground level

Stage 4 – escape at ground level away from the building.

It is important that each floor plan of a building indicates the shortest route(s) to a place of

comparative or ultimate safety should an emergency evacuation be triggered, e.g. by the

sounding of the fire alarm. The width of final exit doors and the escape routes leading to them

will dictate the maximum number of people who can safely occupy that floor or a specific area

within it under normal conditions of operation.

Review Questions

1. Explain Behaviour of fire.

2.

Define fire safety standards.3. Explain igniter.

4. What concepts in fire protection?

5. Describe Classification of buildings based on occupancy.

6. Explain Passive and active fire precautions.

7. Explain site planning and fire brigade access.

8. Define Roof covering – control of fire spread.



9. Explain Heat sensitive detectors.

10. What is smoke detectors?

11. Describe Automatic water system.

12. Explain Means of escape, design and planning of escape halts and corridors to final exit.

water supply sanitation fire

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